:: Quasi-uniform Space
:: by Roland Coghetto
::
:: Received June 30, 2016
:: Copyright (c) 2016-2018 Association of Mizar Users
:: (Stowarzyszenie Uzytkownikow Mizara, Bialystok, Poland).
:: This code can be distributed under the GNU General Public Licence
:: version 3.0 or later, or the Creative Commons Attribution-ShareAlike
:: License version 3.0 or later, subject to the binding interpretation
:: detailed in file COPYING.interpretation.
:: See COPYING.GPL and COPYING.CC-BY-SA for the full text of these
:: licenses, or see http://www.gnu.org/licenses/gpl.html and
:: http://creativecommons.org/licenses/by-sa/3.0/.
environ
vocabularies EQREL_1, YELLOW_6, FINTOPO7, SIMPLEX0, FINTOPO2, RELAT_2,
PRE_TOPC, FUNCT_1, STRUCT_0, CARD_1, XBOOLE_0, SUBSET_1, SETFAM_1,
TARSKI, ZFMISC_1, RELAT_1, CARD_FIL, WAYBEL_0, ARYTM_3, CANTOR_1,
FILTER_0, XXREAL_1, PCOMPS_1, RCOMP_1, FINSUB_1, PARTFUN1, TEX_1,
FINSET_1, TOLER_1, NAT_1, XCMPLX_0, UNIFORM2, FINSEQ_1;
notations TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, SETFAM_1, RELAT_1, FUNCT_1,
RELAT_2, ORDINAL1, RELSET_1, PARTFUN1, MCART_1, FUNCT_2, DOMAIN_1,
CANTOR_1, FINSET_1, NAT_1, SIMPLEX0, CARD_FIL, EQREL_1, TEX_1, STRUCT_0,
CARDFIL2, FINSUB_1, FINTOPO2, FINTOPO7, TOLER_1, PRE_TOPC, CARD_1;
constructors NAT_1, CARDFIL2, TOPMETR, FINSUB_1, FINTOPO7, CANTOR_1, TEX_1;
registrations CARD_1, PARTFUN1, RELAT_1, ZFMISC_1, XBOOLE_0, SUBSET_1,
ORDINAL1, RELSET_1, STRUCT_0, FINTOPO7, PRE_TOPC, CANTOR_1, FINSET_1;
requirements NUMERALS, SUBSET, BOOLE;
definitions TARSKI, XBOOLE_0, ROUGHS_4;
equalities TARSKI, SUBSET_1, FINTOPO7, RELAT_1, TEX_1;
expansions CARDFIL2, TARSKI, XBOOLE_0, FINTOPO7;
theorems SYSREL, ROUGHS_4, TARSKI, RELAT_1, FUNCT_2, FUNCT_1, XBOOLE_1,
CARDFIL2, ZFMISC_1, XBOOLE_0, SETFAM_1, XTUPLE_0, CARD_FIL, FINSUB_1,
SUBSET_1, FINTOPO2, FINTOPO7, PRE_TOPC, CANTOR_1, RELAT_2, PARTIT_2,
PREFER_1, ORDERS_1, PARTFUN1, TAXONOM1, MSSUBFAM, ARMSTRNG, TOPS_1,
CARD_2, STIRL2_1, ENUMSET1;
schemes NAT_1, FUNCT_2, FRAENKEL;
begin :: Preliminaries
reserve X for set,
A for Subset of X,
R,S for Relation of X;
theorem Th2:
[:X \ A,X:] \/ [:X,A:] c= [:X,X:]
proof
[:X,A:] c= [:X,X:] & [:X \ A,X:] c= [:X,X:] by ZFMISC_1:95;
hence thesis by XBOOLE_1:8;
end;
theorem
[:X \ A,X:] \/ [:X,A:] = [:A,A:] \/ [:X \ A,X:]
proof
A1: [:X \ A,X:] \/ [:X,A:] c= [:A,A:] \/ [:X\A,X:]
proof
let x be object;
assume
A2: x in [:X \ A,X:] \/ [:X,A:];
[:X \ A,X:] \/ [:X,A:] c= [:X,X:] by Th2;
then consider a,b be object such that
A3: a in X and
A4: b in X and
A5: x = [a,b] by A2,ZFMISC_1:def 2;
per cases;
suppose
A6: a in A;
x in [:X,A:]
proof
assume not x in [:X,A:];
then x in [:X \ A,X:] by A2,XBOOLE_0:def 3;
then a in X \ A & b in X by A5,ZFMISC_1:87;
hence contradiction by A6,XBOOLE_0:def 5;
end;
then b in A by A5,ZFMISC_1:87; then
A7: x in [:A,A:] by A6,A5,ZFMISC_1:87;
[:A,A:] c= [:A,A:] \/ [:X\A,X:] by XBOOLE_1:7;
hence thesis by A7;
end;
suppose not a in A;
then a in X \ A by A3,XBOOLE_0:def 5; then
A8: x in [:X\A,X:] by A4,A5,ZFMISC_1:87;
[:X\A,X:] c= [:X\A,X:] \/ [:A,A:] by XBOOLE_1:7;
hence thesis by A8;
end;
end;
[:A,A:] c= [:X,A:] by ZFMISC_1:95;
hence thesis by A1,XBOOLE_1:13;
end;
theorem Th3:
R * S = {[x,y] where x,y is Element of X : ex z being Element of X st
[x,z] in R & [z,y] in S}
proof
reconsider RS = R * S as Relation of X;
A1: R * S c= {[x,y] where x,y is Element of X : ex z being Element of X
st [x,z] in R & [z,y] in S}
proof
let t be object;
assume
A1: t in R * S;
consider x1,x2 be object such that
x1 in X and
A2: x2 in X and
A3: t = [x1,x2] by A1,ZFMISC_1:def 2;
consider z be object such that
A4: [x1,z] in R and
A5: [z,x2] in S by A1,A3,RELAT_1:def 8;
reconsider x1,x2,z1 = z as Element of X by A2,A4,ZFMISC_1:87;
[x1,z1] in R & [z1,x2] in S by A4,A5;
hence thesis by A3;
end;
{[x,y] where x,y is Element of X : ex z being Element of X st [x,z] in R &
[z,y] in S} c= R * S
proof
let t be object;
assume t in {[x,y] where x,y is Element of X : ex z being Element of X
st [x,z] in R & [z,y] in S};
then ex x,y be Element of X st t = [x,y] & ex z being Element of X st
[x,z] in R & [z,y] in S;
hence thesis by RELAT_1:def 8;
end;
hence thesis by A1;
end;
registration
let X be set, cB be Subset-Family of X;
cluster <.cB.] -> non empty;
coherence
proof
per cases;
suppose
cB is empty;
hence thesis by CARDFIL2:15;
end;
suppose
A1: cB is non empty;
cB c= <.cB.] by CARDFIL2:18;
hence thesis by A1;
end;
end;
end;
registration
let X be set, cB be Subset-Family of [:X,X:];
cluster -> Relation-like for Element of cB;
coherence
proof
let e be Element of cB;
per cases;
suppose cB is non empty;
then e in cB;
hence thesis;
end;
suppose cB is empty;
hence thesis by SUBSET_1:def 1;
end;
end;
end;
notation
let X be set, cB be Subset-Family of [:X,X:],
B be Element of cB;
synonym B[~] for B~;
end;
definition
let X be set, cB be Subset-Family of [:X,X:],
B be Element of cB;
redefine func B[~] -> Subset of [:X,X:];
coherence
proof
per cases;
suppose
A3: cB is non empty;
B~ c= [:X,X:]
proof
let x be object;
assume
A0: x in B~;
then consider a,b being object such that
A1: x = [a,b] by RELAT_1:def 1;
A2: [b,a] in B by A0,A1,RELAT_1:def 7;
B in cB by A3;
then b in X & a in X by A2,ZFMISC_1:87;
hence thesis by A1,ZFMISC_1:87;
end;
hence thesis;
end;
suppose cB is empty;
then B = {} by SUBSET_1:def 1;
then B~ = {};
hence thesis by XBOOLE_1:2;
end;
end;
end;
notation
let X be set, cB be Subset-Family of [:X,X:];
let B1,B2 be Element of cB;
synonym B1 [*] B2 for B1 * B2;
end;
definition
let X be set, cB be Subset-Family of [:X,X:];
let B1,B2 be Element of cB;
redefine func B1 [*] B2 -> Subset of [:X,X:];
coherence
proof
per cases;
suppose
A3: cB is non empty;
B1*B2 c= [:X,X:]
proof
let x be object;
assume
A0: x in B1*B2;
then consider a,b being object such that
A1: x = [a,b] by RELAT_1:def 1;
consider c being object such that
A2: [a,c] in B1 & [c,b] in B2 by A0,A1,RELAT_1:def 8;
B1 in cB & B2 in cB by A3;
then b in X & a in X by A2,ZFMISC_1:87;
hence thesis by A1,ZFMISC_1:87;
end;
hence thesis;
end;
suppose cB is empty;
then B1 = {} & B2 = {} by SUBSET_1:def 1;
then B1*B2 = {};
hence thesis by XBOOLE_1:2;
end;
end;
end;
theorem
for X being set,G being Subset-Family of X st G is upper holds
FinMeetCl G is upper
proof
let X be set, G be Subset-Family of X;
assume
A1: G is upper;
now
let Y1,Y2 be Subset of X;
assume that
A2: Y1 in FinMeetCl G and
A3: Y1 c= Y2;
consider Z being Subset-Family of X such that
A4: Z c= G and
A5: Z is finite and
A6: Y1 = Intersect Z by A2,CANTOR_1:def 3;
per cases;
suppose
A7: Z is empty;
then Y2 = X by A6,A3,SETFAM_1:def 9;
hence Y2 in FinMeetCl G by A7,A6,SETFAM_1:def 9,A2;
end;
suppose
A8: Z is non empty;
set Z2 = the set of all z \/ Y2 where z is Element of Z;
set a = the Element of Z;
A9: a \/ Y2 in Z2;
Z2 c= bool X
proof
let t be object;
assume t in Z2;
then consider u be Element of Z such that
A10: t = u \/ Y2;
A11: u in Z by A8;
u \/ Y2 c= X by XBOOLE_1:8,A11;
hence thesis by A10;
end;
then reconsider Z2 as Subset-Family of X;
now
now
let x be object;
assume
A12: x in Z2;
then reconsider y = x as Subset of X;
consider u be Element of Z such that
A13: y = u \/ Y2 by A12;
u in G by A8,A4;
hence x in G by A13,XBOOLE_1:7,A1;
end;
hence Z2 c= G;
A14: Z is finite by A5;
deffunc F(Element of Z) = $1 \/ Y2;
A15: {F(z) where z is Element of Z:z in Z} is finite
from FRAENKEL:sch 21(A14);
now
thus {F(z) where z is Element of Z:z in Z} c= Z2
proof
let x be object;
assume x in {F(z) where z is Element of Z:z in Z};
then ex z be Element of Z st x = F(z) & z in Z;
hence thesis;
end;
thus Z2 c= {F(z) where z is Element of Z:z in Z}
proof
let x be object;
assume x in Z2;
then ex z be Element of Z st x = z \/ Y2;
hence thesis by A8;
end;
end;
hence Z2 is finite by A15;
now
thus Y2 c= meet Z2
proof
let x be object;
assume
A16: x in Y2;
now
let YY be set;
assume
A17: YY in Z2;
then reconsider ZZ = YY as Subset of X;
consider u be Element of Z such that
A18: ZZ = u \/ Y2 by A17;
Y2 c= u \/ Y2 by XBOOLE_1:7;
hence x in YY by A16,A18;
end;
hence thesis by A9,SETFAM_1:def 1;
end;
thus meet Z2 c= Y2
proof
let x be object;
assume
A19: x in meet Z2;
A20: for z be Element of Z holds x in z \/ Y2
proof
let z be Element of Z;
z \/ Y2 in Z2;
hence thesis by A19,SETFAM_1:def 1;
end;
for z be Element of Z holds (x in z or x in Y2)
proof
let z be Element of Z;
x in z \/ Y2 by A20;
hence thesis by XBOOLE_0:def 3;
end;
then (for z be set st z in Z holds x in z) or x in Y2;
then (x in meet Z) or x in Y2 by A8,SETFAM_1:def 1;
then x in (meet Z) \/ Y2 by XBOOLE_0:def 3; then
A21: x in Y1 \/ Y2 by A8,A6,SETFAM_1:def 9;
Y1 \/ Y2 c= Y2 by A3,XBOOLE_1:8;
hence thesis by A21;
end;
end;
hence Y2 = Intersect Z2 by A9,SETFAM_1:def 9;
end;
hence Y2 in FinMeetCl G by CANTOR_1:def 3;
end;
end;
hence thesis;
end;
theorem Th4:
R is_symmetric_in X implies R~ is_symmetric_in X
proof
assume
A1: R is_symmetric_in X;
now
let x,y be object;
assume that
A2: x in X and
A3: y in X and
A4: [x,y] in R~;
[y,x] in R by A4,RELAT_1:def 7;
then [x,y] in R by A2,A3,A1,RELAT_2:def 3;
hence [y,x] in R~ by RELAT_1:def 7;
end;
hence thesis by RELAT_2:def 3;
end;
begin :: Uniform Space Structure
definition
struct (1-sorted)
UniformSpaceStr
(# carrier -> set,
entourages -> Subset-Family of [:the carrier,the carrier:] #);
end;
definition
let U be UniformSpaceStr;
attr U is void means
the entourages of U is empty;
end;
definition
let X be set;
func Uniform_Space(X) -> strict UniformSpaceStr equals
UniformSpaceStr (# X , {} bool[:X,X:] #);
coherence;
end;
definition
func TrivialUniformSpace -> strict UniformSpaceStr equals
UniformSpaceStr (# {} , cobool[:{},{}:] #);
coherence;
func NonEmptyTrivialUniformSpace -> strict UniformSpaceStr means :D1:
ex SF being Subset-Family of [:{{}},{{}}:] st SF = {[:{{}},{{}}:]} &
it = UniformSpaceStr (#{{}},SF#);
existence
proof
set X = {{}};
reconsider SF = {[:X,X:]} as Subset-Family of [:X,X:] by ZFMISC_1:68;
take UniformSpaceStr(# X,SF #);
thus thesis;
end;
uniqueness;
end;
registration
let X be empty set;
cluster Uniform_Space(X) -> empty;
coherence;
end;
registration
let X be non empty set;
cluster Uniform_Space(X) -> non empty;
coherence;
end;
registration
let X be set;
cluster Uniform_Space(X) -> void;
coherence;
end;
registration
cluster TrivialUniformSpace -> empty non void;
coherence;
cluster NonEmptyTrivialUniformSpace -> non empty non void;
coherence
proof
ex SF being Subset-Family of [:{{}},{{}}:] st SF = {[:{{}},{{}}:]} &
NonEmptyTrivialUniformSpace = UniformSpaceStr (#{{}},SF#) by D1;
hence thesis;
end;
end;
registration
cluster empty strict void for UniformSpaceStr;
existence
proof
take Uniform_Space{};
thus thesis;
end;
cluster empty strict non void for UniformSpaceStr;
existence
proof
take TrivialUniformSpace;
thus thesis;
end;
cluster non empty strict void for UniformSpaceStr;
existence
proof
take Uniform_Space{{}};
thus thesis;
end;
cluster non empty strict non void for UniformSpaceStr;
existence
proof
take NonEmptyTrivialUniformSpace;
thus thesis;
end;
end;
definition
let X be set, SF be Subset-Family of [:X,X:];
func SF[~] -> Subset-Family of [:X,X:] equals
the set of all S[~] where S is Element of SF;
coherence
proof
the set of all S[~] where S is Element of SF c= bool [:X,X:]
proof
let x be object;
assume x in the set of all S[~] where S is Element of SF;
then ex S be Element of SF st x = S[~];
hence thesis;
end;
hence thesis;
end;
end;
definition
let US be UniformSpaceStr;
func US[~] -> UniformSpaceStr equals
UniformSpaceStr(# the carrier of US, (the entourages of US)[~] #);
coherence;
end;
registration
let USS be non empty UniformSpaceStr;
cluster USS[~] -> non empty;
coherence;
end;
begin :: Axioms
definition
let US be UniformSpaceStr;
attr US is upper means
the entourages of US is upper;
attr US is cap-closed means
the entourages of US is cap-closed;
attr US is axiom_U1 means
for S being Element of the entourages of US holds
id the carrier of US c= S;
attr US is axiom_U2 means
for S being Element of the entourages of US holds
S[~] in the entourages of US;
attr US is axiom_U3 means
for S being Element of the entourages of US holds
ex W being Element of the entourages of US st W [*] W c= S;
end;
theorem Th7:
for US being non void UniformSpaceStr holds
US is axiom_U1 iff for S being Element of the entourages of US holds
ex R being Relation of the carrier of US st R = S &
R is_reflexive_in the carrier of US
proof
let US be non void UniformSpaceStr;
US is non void;
then reconsider SFX = the entourages of US as non empty
Subset-Family of [:the carrier of US,the carrier of US:];
hereby
assume
A1: US is axiom_U1;
now
let S be Element of the entourages of US;
S is Element of SFX;
then consider R be Relation of the carrier of US such that
A2: R = S;
take R;
thus R = S by A2;
now
let x be object;
assume x in the carrier of US; then
A3: [x,x] in id the carrier of US by RELAT_1:def 10;
id the carrier of US c= S by A1;
hence [x,x] in R by A3,A2;
end;
hence R is_reflexive_in the carrier of US by RELAT_2:def 1;
end;
hence for S being Element of the entourages of US holds
ex R being Relation of the carrier of US st (R = S &
R is_reflexive_in the carrier of US);
end;
assume
A4: for S being Element of the entourages of US ex R being Relation of
the carrier of US st (R = S & R is_reflexive_in the carrier of US);
now
let S be Element of the entourages of US;
consider R be Relation of the carrier of US such that
A5: R = S and
A6: R is_reflexive_in the carrier of US by A4;
for x be object st x in the carrier of US holds [x,x] in R
by A6,RELAT_2:def 1;
hence id the carrier of US c= S by A5,RELAT_1:47;
end;
hence US is axiom_U1;
end;
theorem Th8:
for US being non void UniformSpaceStr holds
US is axiom_U1 iff for S being Element of the entourages of US
ex R being total reflexive Relation of the carrier of US st R = S
proof
let US be non void UniformSpaceStr;
US is non void;
then reconsider SFX = the entourages of US as non empty
Subset-Family of [:the carrier of US,the carrier of US:];
hereby
assume
A2: US is axiom_U1;
hereby
let S being Element of the entourages of US;
consider R being Relation of the carrier of US such that
A3: R = S and
A4: R is_reflexive_in the carrier of US by A2,Th7;
A5: field R = the carrier of US by A4,PARTIT_2:9;
reconsider R as total reflexive Relation of the carrier of US
by A5,A4,TAXONOM1:3,PARTFUN1:def 2,RELAT_2:def 9;
take R;
thus R = S by A3;
end;
end;
assume
A6: for S being Element of the entourages of US holds
ex R being total reflexive Relation of the carrier of US st R = S;
now
let S being Element of the entourages of US;
consider R being total reflexive Relation of the carrier of US such that
A7: R = S by A6;
reconsider R as Relation of the carrier of US;
take R;
thus R = S by A7;
now
let x be object;
assume
A8: x in the carrier of US;
field R = the carrier of US by ORDERS_1:12;
hence [x,x] in R by A8,RELAT_2:def 9,RELAT_2:def 1;
end;
hence R is_reflexive_in the carrier of US by RELAT_2:def 1;
end;
hence US is axiom_U1 by Th7;
end;
registration
cluster void -> non axiom_U2 for UniformSpaceStr;
coherence;
end;
theorem
for US being UniformSpaceStr st US is axiom_U2 holds
for S being Element of the entourages of US holds
(for x,y being Element of US st [x,y] in S holds
[y,x] in union the entourages of US)
proof
let US be UniformSpaceStr;
assume
A1: US is axiom_U2;
let S be Element of the entourages of US;
let x,y be Element of US;
assume
A3: [x,y] in S;
reconsider SFX = the entourages of US as non empty
Subset-Family of [:the carrier of US,the carrier of US:] by A1;
A6: [y,x] in S~ by A3,RELAT_1:def 7;
S~ in the entourages of US by A1;
hence thesis by A6,TARSKI:def 4;
end;
theorem Th9:
for US being non void UniformSpaceStr st
for S being Element of the entourages of US holds
ex R being Relation of the carrier of US st S = R &
R is_symmetric_in the carrier of US holds US is axiom_U2
proof
let US be non void UniformSpaceStr;
assume
A2: for S being Element of the entourages of US holds
ex R being Relation of the carrier of US st S = R &
R is_symmetric_in the carrier of US;
A1: US is non void;
US is axiom_U2
proof
let S be Element of the entourages of US;
consider R being Relation of the carrier of US such that
A3: S = R and
A4: R is_symmetric_in the carrier of US by A2;
thus S~ in the entourages of US
proof
R~ = R
proof
thus R~ c= R
proof
let x be object;
assume
A7: x in R~;
then consider a,b be object such that
A8: a in the carrier of US and
A9: b in the carrier of US and
A10: x = [a,b] by ZFMISC_1:def 2;
[b,a] in R by A7,A10,RELAT_1:def 7;
hence thesis by A10,A4,A8,A9,RELAT_2:def 3;
end;
let x be object;
assume
A11: x in R;
then consider a,b be object such that
A12: a in the carrier of US and
A13: b in the carrier of US and
A14: x = [a,b] by ZFMISC_1:def 2;
[b,a] in R~ by A11,A14,RELAT_1:def 7;
hence thesis by Th4,A4,A12,A13,A14,RELAT_2:def 3;
end;
hence thesis by A1,A3;
end;
end;
hence thesis;
end;
theorem Th10:
for US being non void UniformSpaceStr st
for S being Element of the entourages of US holds
ex R being Relation of the carrier of US st S = R &
R is symmetric holds US is axiom_U2
proof
let US be non void UniformSpaceStr;
assume
A2: for S being Element of the entourages of US ex
R being Relation of the carrier of US st S = R & R is symmetric;
now
let S be Element of the entourages of US;
consider R being Relation of the carrier of US such that
B1: S = R and
B2: R is symmetric by A2;
take R;
thus S = R by B1;
for x,y be object st x in the carrier of US & y in the carrier of US &
[x,y] in R holds [y,x] in R by B2,PREFER_1:20;
hence R is_symmetric_in the carrier of US by RELAT_2:def 3;
end;
hence thesis by Th9;
end;
theorem
for US being non void UniformSpaceStr st
for S being Element of the entourages of US holds
ex R being Tolerance of the carrier of US st S = R holds US is axiom_U1 &
US is axiom_U2
proof
let US be non void UniformSpaceStr;
assume
A2: for S being Element of the entourages of US holds
ex R being Tolerance of the carrier of US st S = R;
for S being Element of the entourages of US holds
ex R being total reflexive Relation of the carrier of US st R = S
proof
let S be Element of the entourages of US;
ex R being Tolerance of the carrier of US st R = S by A2;
hence thesis;
end;
hence US is axiom_U1 by Th8;
for S being Element of the entourages of US holds
ex R being Relation of the carrier of US st S = R & R is symmetric
proof
let S be Element of the entourages of US;
ex R being Tolerance of the carrier of US st S = R by A2;
hence thesis;
end;
hence US is axiom_U2 by Th10;
end;
registration
let X be empty set;
cluster Uniform_Space(X) ->
upper cap-closed axiom_U1 non axiom_U2 axiom_U3;
coherence
proof
set US = Uniform_Space(X);
set E = the entourages of US;
thus E is upper;
thus E is cap-closed
proof
let Y1,Y2 be Subset of [:the carrier of US,the carrier of US:];
thus thesis;
end;
thus for S being Element of E holds id the carrier of US c= S;
thus US is non axiom_U2;
let S be Element of E;
S [*] S c= S;
hence thesis;
end;
end;
registration
cluster Uniform_Space{{}} -> upper cap-closed non axiom_U2;
coherence
proof
set US = Uniform_Space{{}};
set E = the entourages of US;
thus E is upper;
thus E is cap-closed
proof
let Y1,Y2 be Subset of [:the carrier of US,the carrier of US:];
thus thesis;
end;
thus US is non axiom_U2;
end;
cluster TrivialUniformSpace -> upper cap-closed axiom_U1 axiom_U2 axiom_U3;
coherence
proof
set US = TrivialUniformSpace;
set E = the entourages of US;
A1: E = {{}} by ENUMSET1:29;
E is upper;
hence US is upper;
for X,Y be set st X in E & Y in E holds X /\ Y in E;
hence US is cap-closed by FINSUB_1:def 2;
for S being Element of E holds id the carrier of US c= S;
hence US is axiom_U1;
now
let S be Element of E;
S in {{}} by A1;
hence S~ in E by A1;
end;
hence US is axiom_U2;
let S be Element of the entourages of US;
S [*] S c= S;
hence thesis;
end;
cluster NonEmptyTrivialUniformSpace ->
upper cap-closed axiom_U1 axiom_U2 axiom_U3;
coherence
proof
set X = {{}};
set US = NonEmptyTrivialUniformSpace;
set E = the entourages of US;
consider SF being Subset-Family of [:X,X:] such that
B1: SF = {[:X,X:]} and
B2: US = UniformSpaceStr (#X,SF#) by D1;
for Y1,Y2 be Subset of [:the carrier of US,the carrier of US:] st
Y1 in E & Y1 c= Y2 holds Y2 in E
proof
let Y1,Y2 be Subset of [:the carrier of US,the carrier of US:];
assume that
A2: Y1 in E and
A3: Y1 c= Y2;
A4: Y1 = [:X,X:] by B1,B2,A2,TARSKI:def 1;
Y1 = Y2 by B2,A3,A4;
hence thesis by A2;
end;
hence E is upper;
for a,b be Subset of [:the carrier of US,the carrier of US:] st
a in E & b in E holds a /\ b in E
proof
let a,b be Subset of [:the carrier of US,the carrier of US:];
assume that
A5: a in E and
A6: b in E;
a = [:X,X:] & b = [:X,X:] by B1,B2,A5,A6,TARSKI:def 1;
hence a /\ b in E by B1,B2,TARSKI:def 1;
end;
hence US is cap-closed by ROUGHS_4:def 2;
for S being Element of E holds id X c= S
proof
let S be Element of E;
S = [:X,X:] by B1,B2,TARSKI:def 1;
hence thesis;
end;
hence US is axiom_U1 by B2;
thus for S being Element of E holds S~ in E
proof
let S be Element of E;
S = [:X,X:] by B1,B2,TARSKI:def 1;
then S~ = [:X,X:] by SYSREL:5;
hence thesis by B1,B2,TARSKI:def 1;
end;
let S be Element of E;
take S;
S = [:X,X:] by B1,B2,TARSKI:def 1;
hence thesis by B2;
end;
end;
registration
cluster strict empty non void upper cap-closed axiom_U1 axiom_U2 axiom_U3
for UniformSpaceStr;
existence
proof
take TrivialUniformSpace;
thus thesis;
end;
end;
registration
cluster empty -> axiom_U1 for strict UniformSpaceStr;
coherence
proof
let US be strict UniformSpaceStr;
assume US is empty;
hence for S being Element of the entourages of US holds
id the carrier of US c= S;
end;
end;
registration
cluster strict non empty non void upper cap-closed axiom_U1 axiom_U2 axiom_U3
for UniformSpaceStr;
existence
proof
take NonEmptyTrivialUniformSpace;
thus thesis;
end;
end;
definition
let SUS be non empty axiom_U1 UniformSpaceStr,
x be Element of SUS,
V be Element of the entourages of SUS;
func Neighborhood(V,x) -> non empty Subset of SUS equals
{y where y is Element of SUS: [x,y] in V};
coherence
proof
A1: {y where y is Element of SUS: [x,y] in V} c=
the carrier of SUS
proof
let z be object;
assume z in {y where y is Element of SUS: [x,y] in V};
then ex y be Element of SUS st z = y & [x,y] in V;
hence thesis;
end;
SUS is axiom_U1; then
A2: id the carrier of SUS c= V;
[x,x] in id the carrier of SUS by RELAT_1:def 10;
then x in {y where y is Element of SUS: [x,y] in V} by A2;
hence thesis by A1;
end;
end;
theorem
for USS being non empty axiom_U1 UniformSpaceStr, x being Element of
the carrier of USS, V being Element of the entourages of USS holds
x in Neighborhood(V,x)
proof
let USS be non empty axiom_U1 UniformSpaceStr,
x be Element of USS,
V be Element of the entourages of USS;
USS is axiom_U1; then
A1: id the carrier of USS c= V;
[x,x] in id the carrier of USS by RELAT_1:def 10;
hence thesis by A1;
end;
definition
let USS be cap-closed UniformSpaceStr,
V1,V2 be Element of the entourages of USS;
redefine func V1 /\ V2 -> Element of the entourages of USS;
coherence
proof
per cases;
suppose the entourages of USS is empty;
then V1 = {} & V2 = {} by SUBSET_1:def 1;
hence thesis;
end;
suppose
A1: the entourages of USS is non empty;
USS is cap-closed;
hence thesis by A1,FINSUB_1:def 2;
end;
end;
end;
theorem Th11:
for USS being non empty cap-closed axiom_U1 UniformSpaceStr,
x being Element of USS,
V,W being Element of the entourages of USS holds
Neighborhood(V,x) /\ Neighborhood(W,x) = Neighborhood(V /\ W,x)
proof
let USS be non empty cap-closed axiom_U1 UniformSpaceStr,
x be Element of USS,
V,W be Element of the entourages of USS;
set NV = Neighborhood(V,x), NW = Neighborhood(W,x),
NVW = Neighborhood(V /\ W,x);
A1: NV /\ NW c= NVW
proof
let t be object;
assume
A2: t in NV /\ NW;
then t in {y where y is Element of USS: [x,y] in V} by XBOOLE_0:def 4;
then consider y1 be Element of USS such that
A3: t = y1 and
A4: [x,y1] in V;
t in {y where y is Element of USS: [x,y] in W} by A2,XBOOLE_0:def 4;
then consider y2 be Element of USS such that
A5: t = y2 and
A6: [x,y2] in W;
[x,y1] in V /\ W & [x,y2] in V /\ W by A3,A4,A5,A6,XBOOLE_0:def 4;
hence thesis by A3;
end;
NVW c= NV /\ NW
proof
let t be object;
assume t in NVW;
then consider y be Element of USS such that
A7: t = y and
A8: [x,y] in V /\ W;
A9: [x,y] in V & [x,y] in W by A8,XBOOLE_0:def 4; then
A10: t in NV by A7;
t in {y where y is Element of USS: [x,y] in W} by A7,A9;
hence t in NV /\ NW by A10,XBOOLE_0:def 4;
end;
hence thesis by A1;
end;
registration
let USS be non empty axiom_U1 UniformSpaceStr;
cluster the entourages of USS -> with_non-empty_elements;
coherence
proof
assume not the entourages of USS is with_non-empty_elements; then
A1: {} in the entourages of USS by SETFAM_1:def 8;
USS is axiom_U1;
then id the carrier of USS c= {} by A1;
hence thesis;
end;
end;
registration
let USS be non empty axiom_U1 UniformSpaceStr;
cluster the entourages of USS -> non empty;
coherence
proof
assume the entourages of USS is empty;
then reconsider S = {} as Element of the entourages of USS
by SUBSET_1:def 1;
USS is axiom_U1;
then id the carrier of USS c= S;
hence thesis;
end;
end;
definition
let USS be non empty axiom_U1 UniformSpaceStr,x being Point of USS;
func Neighborhood(x) -> Subset-Family of USS equals
the set of all Neighborhood(V,x) where V is Element of the entourages of USS;
coherence
proof
set SN = the set of all Neighborhood(V,x) where V is Element of
the entourages of USS;
SN c= bool the carrier of USS
proof
let t be object;
assume t in SN;
then ex V be Element of the entourages of USS st t = Neighborhood(V,x);
hence thesis;
end;
hence thesis;
end;
end;
registration
let USS be non empty axiom_U1 UniformSpaceStr,x being Point of USS;
cluster Neighborhood(x) -> non empty;
coherence
proof
set SN = Neighborhood(x);
the entourages of USS is non empty;
then consider V0 be object such that
A2: V0 in the entourages of USS;
reconsider V1 = V0 as Element of the entourages of USS by A2;
Neighborhood(V1,x) in SN;
hence thesis;
end;
end;
theorem
for SUS being non empty axiom_U1 UniformSpaceStr, x being Element of
the carrier of SUS, V being Element of the entourages of SUS holds
Neighborhood(V,x) = V.:{x} & Neighborhood(V,x) = rng(V|{x}) &
Neighborhood(V,x) = Im(V,x) & Neighborhood(V,x) = Class(V,x) &
Neighborhood(V,x) = neighbourhood(x,V)
proof
let SUS be non empty axiom_U1 UniformSpaceStr, x be Element of
the carrier of SUS, V be Element of the entourages of SUS;
thus Neighborhood(V,x) = V.:{x}
proof
thus Neighborhood(V,x) c= V.:{x}
proof
let t be object;
assume t in Neighborhood(V,x);
then consider y be Element of SUS such that
A3: t = y and
A4: [x,y] in V;
x in {x} by TARSKI:def 1;
hence thesis by A3,A4,RELAT_1:def 13;
end;
let t be object;
assume t in V.:{x};
then consider v be object such that
A5: [v,t] in V and
A6: v in {x} by RELAT_1:def 13;
A7: t in the carrier of SUS by A5,ZFMISC_1:87;
[x,t] in V by A5,A6,TARSKI:def 1;
hence thesis by A7;
end;
hence thesis by RELAT_1:115;
end;
definition
let USS be non empty axiom_U1 UniformSpaceStr;
func Neighborhood(USS) -> Function of the carrier of USS,bool bool
the carrier of USS means :Def5:
for x being Element of USS holds it.x = Neighborhood(x);
existence
proof
defpred P[object,object] means ex x be Element of USS st
x = $1 & $2 = Neighborhood(x);
A1: for x be object st x in the carrier of USS ex y be object st
y in bool bool the carrier of USS & P[x,y]
proof
let x be object;
assume x in the carrier of USS;
then reconsider y = x as Element of USS;
take z = Neighborhood(y);
thus z in bool bool the carrier of USS;
thus P[x,z];
end;
consider f be Function of the carrier of USS, bool bool the carrier of USS
such that
A2: for x be object st x in the carrier of USS holds P[x,f.x]
from FUNCT_2:sch 1(A1);
take f;
hereby
let x be Element of USS;
P[x,f.x] by A2;
hence f.x = Neighborhood(x);
end;
end;
uniqueness
proof
let F1,F2 be Function of the carrier of USS,bool bool the carrier of USS
such that
A3: for x be Element of USS holds
F1.x = Neighborhood(x) and
A4: for x be Element of USS holds
F2.x = Neighborhood(x);
now
thus dom F1 = the carrier of USS by FUNCT_2:def 1
.= dom F2 by FUNCT_2:def 1;
hereby
let x be object;
assume x in dom F1;
then reconsider y = x as Element of USS;
F1.y = Neighborhood(y) by A3;
hence F1.x = F2.x by A4;
end;
end;
hence thesis by FUNCT_1:def 11;
end;
end;
definition
let USS be non empty axiom_U1 UniformSpaceStr;
attr USS is topological means
FMT_Space_Str(# the carrier of USS,Neighborhood(USS) #) is FMT_TopSpace;
end;
begin :: Quasi-Uniform Space
definition
mode Quasi-UniformSpace is upper cap-closed axiom_U1 axiom_U3
UniformSpaceStr;
end;
reserve QUS for Quasi-UniformSpace;
theorem
the entourages of QUS is empty implies the entourages of QUS[~] = {{}}
proof
assume
A1: the entourages of QUS is empty;
reconsider EQUS = the entourages of QUS as Subset-Family of
[:the carrier of QUS,the carrier of QUS:];
set X = the set of all U~ where U is Element of the entourages of QUS;
X = {{}}
proof
thus X c= {{}}
proof
let x be object;
assume x in X;
then consider U be Element of the entourages of QUS such that
A11: x = U~;
U = {} by A1,SUBSET_1:def 1;
then x = {} by A11;
hence thesis by TARSKI:def 1;
end;
let x be object;
assume x in {{}}; then
A14: x = {} by TARSKI:def 1;
then reconsider y = x as Element of the entourages of QUS
by A1,SUBSET_1:def 1;
y~ = {} by A14;
hence thesis by A14;
end;
hence thesis;
end;
theorem
the entourages of QUS[~] = {{}} & the entourages of QUS[~] is upper
implies the carrier of QUS is empty
proof
assume that
A1: the entourages of QUS[~] = {{}} and
A2: the entourages of QUS[~] is upper;
reconsider X = the carrier of QUS as set;
[:X,X:] c= [:the carrier of QUS[~],the carrier of QUS[~]:];
then reconsider XX =
[:X,X:] as Subset of [:the carrier of QUS[~],the carrier of QUS[~]:];
{} c= [:the carrier of QUS[~],the carrier of QUS[~]:];
then reconsider Y =
{} as Subset of [:the carrier of QUS[~],the carrier of QUS[~]:];
Y in the entourages of QUS[~] & Y c= XX by A1,TARSKI:def 1;
then XX in the entourages of QUS[~] by A2;
hence thesis by A1,TARSKI:def 1;
end;
registration
let QUS be non void Quasi-UniformSpace;
cluster QUS[~] -> upper cap-closed axiom_U1 axiom_U3;
coherence
proof
A1: QUS is non void;
reconsider EQUS = the entourages of QUS as Subset-Family of
[:the carrier of QUS,the carrier of QUS:];
A10: the entourages of QUS[~] is non empty
proof
assume
A11: the entourages of QUS[~] is empty;
set S = the Element of the entourages of QUS;
reconsider S as Element of the entourages of QUS;
S~ in (the entourages of QUS)[~];
hence contradiction by A11;
end;
for Y1,Y2 being Subset of [:the carrier of QUS[~],the carrier of QUS[~]:]
st Y1 in the entourages of QUS[~] & Y1 c= Y2 holds Y2 in
the entourages of QUS[~]
proof
let Y1,Y2 be Subset of [:the carrier of QUS[~],the carrier of QUS[~]:];
assume that
A12: Y1 in the entourages of QUS[~] and
A13: Y1 c= Y2;
consider U1 be Element of the entourages of QUS such that
A14: Y1 = U1~ by A12;
A15: Y1~ = U1 by A14;
QUS is upper;
then reconsider U2 = Y2~ as Element of the entourages of QUS
by A13,SYSREL:11,A15,CARDFIL2:def 1,A1;
consider R2 be Relation of the carrier of QUS such that
A16: Y2 = R2 and
Y2~ = R2~;
U2~ = (R2~)~ by A16;
hence thesis;
end;
then the entourages of QUS[~] is upper;
hence QUS[~] is upper;
for Y1,Y2 be set st
Y1 in the entourages of QUS[~] & Y2 in the entourages of QUS[~]
holds Y1 /\ Y2 in the entourages of QUS[~]
proof
let Y1,Y2 be set;
assume that
A17: Y1 in the entourages of QUS[~] and
A18: Y2 in the entourages of QUS[~];
consider U1 be Element of the entourages of QUS such that
A19: Y1 = U1~ by A17;
consider U2 be Element of the entourages of QUS such that
A20: Y2 = U2~ by A18;
reconsider U12 = U1 /\ U2 as Element of the entourages of QUS;
Y1 /\ Y2 = U12~ by A19,A20,RELAT_1:22;
hence thesis;
end;
hence QUS[~] is cap-closed by FINSUB_1:def 2;
thus for S being Element of the entourages of QUS[~] holds
id the carrier of QUS[~] c= S
proof
let S be Element of the entourages of QUS[~];
S in the set of all U~ where U is Element of the entourages of QUS
by A10;
then consider U be Element of the entourages of QUS such that
A21: S = U~;
QUS is axiom_U1;
then (id the carrier of QUS)~ c= U~ by SYSREL:11;
hence thesis by A21;
end;
thus for S being Element of the entourages of QUS[~] holds
ex W being Element of the entourages of QUS[~] st W * W c= S
proof
let S be Element of the entourages of QUS[~];
S in the entourages of QUS[~] by A10;
then consider U be Element of the entourages of QUS such that
A24: S = U~;
QUS is axiom_U3;
then consider W be Element of the entourages of QUS such that
A27: W * W c= U;
W~ in (the entourages of QUS)[~];
then reconsider W2 = W[~] as Element of the entourages of QUS[~];
take W2;
let t be object;
assume
A30: t in W2 * W2;
t in {[x,y] where x,y is Element of QUS :
ex z being Element of QUS st [x,z] in W2 & [z,y] in W2} by A30,Th3;
then consider x,y be Element of QUS such that
A34: t = [x,y] and
A35: ex z being Element of QUS st [x,z] in W2 &
[z,y] in W2;
consider z be Element of QUS such that
A36: [x,z] in W2 and
A37: [z,y] in W2 by A35;
A38: [z,x] in W~ ~ by A36,RELAT_1:def 7;
[y,z] in W~ ~ by A37,RELAT_1:def 7;
then [y,x] in W * W by A38,RELAT_1:def 8;
hence thesis by A24,A34,A27,RELAT_1:def 7;
end;
end;
end;
definition
let X be set, cB be Subset-Family of [:X,X:];
attr cB is axiom_UP1 means
for B being Element of cB holds id X c= B;
attr cB is axiom_UP3 means
for B1 being Element of cB ex B2 being Element of cB st B2 [*] B2 c= B1;
end;
theorem
for X being non empty set,cB being empty Subset-Family of [:X,X:] holds
not cB is axiom_UP1
proof
let X be non empty set,
cB be empty Subset-Family of [:X,X:];
assume
A1: cB is axiom_UP1;
{} is Element of cB by SUBSET_1:def 1;
then id X c= {} by A1;
hence thesis;
end;
theorem Th11bis:
for X being set,cB being Subset-Family of [:X,X:] st cB is quasi_basis &
cB is axiom_UP1 & cB is axiom_UP3 holds
UniformSpaceStr(# X,<.cB.] #) is Quasi-UniformSpace
proof
let X be set, cB be Subset-Family of [:X,X:];
assume that
A1: cB is quasi_basis and
A2: cB is axiom_UP1 and
A4: cB is axiom_UP3;
set US = UniformSpaceStr(# X,<.cB.] #);
A5: <.cB.] = {x where x is Subset of [:X,X:]: ex b be Element of cB st
b c= x} by CARDFIL2:14;
now
for Y1,Y2 being Subset of [:X,X:] st Y1 in <.cB.] & Y1 c= Y2 holds
Y2 in <.cB.]
proof
let Y1,Y2 be Subset of [:X,X:];
assume that
A6: Y1 in <.cB.] and
A7: Y1 c= Y2;
consider x be Subset of [:X,X:] such that
A8: Y1 = x and
A9: ex b be Element of cB st b c= x by A5,A6;
consider B be Element of cB such that
A10: B c= x by A9;
B c= Y2 by A10,A8,A7;
hence thesis by A5;
end;
then <.cB.] is upper;
hence US is upper;
for Y1,Y2 be set st Y1 in <.cB.] & Y2 in <.cB.] holds Y1 /\ Y2 in <.cB.]
proof
let Y1,Y2 be set;
assume that
A11: Y1 in <.cB.] and
A12: Y2 in <.cB.];
consider x be Subset of [:X,X:] such that
A13: Y1 = x and
A14: ex b be Element of cB st b c= x by A5,A11;
consider B1 be Element of cB such that
A15: B1 c= x by A14;
Y2 in {x where x is Subset of [:X,X:]: ex b be Element of cB st
b c= x} by CARDFIL2:14,A12;
then consider y be Subset of [:X,X:] such that
A16: Y2 = y and
A17: ex b be Element of cB st b c= y;
consider B2 be Element of cB such that
A18: B2 c= y by A17;
A19: B1 /\ B2 c= Y1 /\ Y2 by A13,A15,A18,A16,XBOOLE_1:27;
consider B3 be Element of cB such that
A20: B3 c= B1 /\ B2 by A1;
A21: Y1 /\ Y2 c= [:X,X:] /\ [:X,X:] by A11,A12,XBOOLE_1:27;
B3 c= Y1 /\ Y2 by A20,A19;
hence thesis by A5,A21;
end;
hence US is cap-closed by FINSUB_1:def 2;
for S being Element of <.cB.] holds id X c= S
proof
let S be Element of <.cB.];
S in {x where x is Subset of [:X,X:]: ex b be Element of cB st
b c= x} by A5;
then consider x be Subset of [:X,X:] such that
A22: S = x and
A23: ex b be Element of cB st b c= x;
consider B be Element of cB such that
A24: B c= x by A23;
id X c= B by A2;
hence thesis by A24,A22;
end;
hence US is axiom_U1;
for S being Element of the entourages of US ex W being
Element of the entourages of US st W * W c= S
proof
let S be Element of the entourages of US;
S in <.cB.];
then consider B1 be Element of cB such that
A31: B1 c= S by CARDFIL2:def 8;
consider B2 be Element of cB such that
A32: B2 * B2 c= B1 by A4;
per cases;
suppose
A34: cB is empty; then
A35: B2 = {} by SUBSET_1:def 1;
{} c= [:X,X:];
then reconsider B2 as Element of the entourages of US
by A35,A34,CARDFIL2:15;
B2 * B2 c= S by A35;
hence thesis;
end;
suppose
A36: cB is non empty;
cB c= <.cB.] by CARDFIL2:18;
then reconsider W = B2 as Element of the entourages of US by A36;
W * W c= S by A31,A32;
hence thesis;
end;
end;
hence US is axiom_U3;
end;
hence thesis;
end;
begin :: Semi-Uniform space
definition
mode Semi-UniformSpace is upper cap-closed axiom_U1 axiom_U2 UniformSpaceStr;
end;
reserve SUS for Semi-UniformSpace;
registration
cluster -> non void for Semi-UniformSpace;
coherence;
end;
theorem Th12:
SUS is empty implies {} in the entourages of SUS
proof
assume
A1: SUS is empty;
assume
A2: not {} in the entourages of SUS;
SUS is non void;
then the entourages of SUS is non empty;
hence thesis by A1,A2;
end;
registration
let SUS be empty Semi-UniformSpace;
cluster the entourages of SUS -> with_empty_element;
coherence by Th12,SETFAM_1:def 8;
end;
begin :: Locally Uniform Space
definition
let SUS be non empty Semi-UniformSpace;
attr SUS is axiom_UL means
for S being Element of the entourages of SUS,
x being Element of SUS holds
ex W being Element of the entourages of SUS st
{y where y is Element of SUS: [x,y] in W [*] W} c= Neighborhood(S,x);
end;
registration
cluster axiom_U3 -> axiom_UL for non empty Semi-UniformSpace;
coherence
proof
let US be non empty Semi-UniformSpace;
assume
A1: US is axiom_U3;
let S be Element of the entourages of US,
x be Element of US;
consider W be Element of the entourages of US such that
A2: W * W c= S by A1;
{y where y is Element of US: [x,y] in W * W} c=
Neighborhood(S,x)
proof
let t be object;
assume t in {y where y is Element of US: [x,y] in W * W};
then ex y0 be Element of US st t = y0 & [x,y0] in W * W;
hence thesis by A2;
end;
hence thesis;
end;
end;
registration
cluster axiom_UL for non empty Semi-UniformSpace;
existence
proof
take the axiom_U3 non empty Semi-UniformSpace;
thus thesis;
end;
end;
definition
mode Locally-UniformSpace is axiom_UL non empty Semi-UniformSpace;
end;
theorem Th15:
for USS being non empty upper axiom_U1 UniformSpaceStr, x being Element of
the carrier of USS holds Neighborhood(x) is upper
proof
let US be non empty upper axiom_U1 UniformSpaceStr,
x be Element of US;
set N = Neighborhood(x);
now
let S1,S2 be Subset of US;
assume that
A1: S1 in N and
A2: S1 c= S2;
consider V1 be Element of the entourages of US such that
A3: S1 = Neighborhood(V1,x) by A1;
A4: V1 c= [:{x},S1:] \/ ([:the carrier of US,the carrier of US:] \
[:{x},the carrier of US:])
proof
let t be object;
assume
A5: t in V1;
consider a,b be object such that
a in the carrier of US and
A7: b in the carrier of US and
A8: t = [a,b] by A5,ZFMISC_1:def 2;
reconsider b as Element of US by A7;
per cases;
suppose
A9: x = a;
then x in {x} & b in S1 by A3,A5,A8,TARSKI:def 1; then
A10: t in [:{x},S1:] by A9,A8,ZFMISC_1:def 2;
[:{x},S1:] c= [:{x},S1:] \/
([:the carrier of US,the carrier of US:] \ [:{x},the carrier of US:])
by XBOOLE_1:7;
hence thesis by A10;
end;
suppose
A11: not x = a;
A12: not [a,b] in [:{x},the carrier of US:]
proof
assume [a,b] in [:{x},the carrier of US:];
then ex c,d be object st c in {x} & d in the carrier of US &
[a,b] = [c,d] by ZFMISC_1:def 2;
then a in {x} & b in the carrier of US by XTUPLE_0:1;
hence thesis by A11,TARSKI:def 1;
end;
A13: t in ([:the carrier of US,the carrier of US:] \
[:{x},the carrier of US:]) by A5,A12,A8,XBOOLE_0:def 5;
[:the carrier of US,the carrier of US:] \ [:{x},the carrier of US:]
c= [:{x},S1:] \/ ([:the carrier of US,the carrier of US:] \
[:{x},the carrier of US:]) by XBOOLE_1:7;
hence thesis by A13;
end;
end;
reconsider V2 = [:{x},S2:] \/ ([:the carrier of US,the carrier of US:]
\ [:{x},the carrier of US:]) as Subset of
[:the carrier of US,the carrier of US:];
A15: V1 c= V2
proof
[:{x},S1:] c= [:{x},S2:] by A2,ZFMISC_1:95;
then [:{x},S1:] \/ ([:the carrier of US,the carrier of US:] \
[:{x},the carrier of US:]) c= [:{x},S2:] \/
([:the carrier of US,the carrier of US:] \
[:{x},the carrier of US:]) by XBOOLE_1:9;
hence thesis by A4;
end;
US is upper;
then the entourages of US is upper;
then reconsider V2 as Element of the entourages of US by A15;
S2 = Neighborhood(V2,x)
proof
A16: S2 c= Neighborhood(V2,x)
proof
let t be object;
assume
A17: t in S2;
then reconsider t1 = t as Element of US;
A18: x in {x} by TARSKI:def 1;
[x,t1] in [:{x},S2:] by A17,A18,ZFMISC_1:def 2;
then [x,t1] in V2 by XBOOLE_0:def 3;
hence thesis;
end;
Neighborhood(V2,x) c= S2
proof
let t be object;
assume t in Neighborhood(V2,x);
then ex y0 be Element of US st t = y0 & [x,y0] in V2;
then per cases by XBOOLE_0:def 3;
suppose [x,t] in [:{x},S2:];
then ex a,b be object st a in {x} & b in S2 & [x,t] = [a,b]
by ZFMISC_1:def 2;
hence thesis by XTUPLE_0:1;
end;
suppose
A19: [x,t] in [:the carrier of US,the carrier of US:] \
[:{x},the carrier of US:];
then ex a,b be object st a in the carrier of US &
b in the carrier of US & [x,t] = [a,b] by ZFMISC_1:def 2; then
A20: t in the carrier of US by XTUPLE_0:1;
x in {x} by TARSKI:def 1;
then [x,t] in [:{x},the carrier of US:] by A20,ZFMISC_1:def 2;
hence thesis by A19,XBOOLE_0:def 5;
end;
end;
hence thesis by A16;
end;
hence S2 in N;
end;
hence thesis;
end;
theorem Th16:
for US being non empty axiom_U1 UniformSpaceStr,
x being Element of US,
V being Element of the entourages of US holds x in Neighborhood(V,x)
proof
let US be non empty axiom_U1 UniformSpaceStr,
x be Element of US,
V be Element of the entourages of US;
US is axiom_U1; then
A1: id the carrier of US c= V;
[x,x] in id the carrier of US by RELAT_1:def 10;
hence thesis by A1;
end;
theorem Th17:
for US being non empty cap-closed axiom_U1 UniformSpaceStr,
x being Element of US holds Neighborhood(x) is cap-closed
proof
let US be non empty cap-closed axiom_U1 UniformSpaceStr,
x be Element of US;
set N = Neighborhood(x);
now
let Y1,Y2 be set;
assume that
A1: Y1 in N and
A2: Y2 in N;
consider V1 be Element of the entourages of US such that
A3: Y1 = Neighborhood(V1,x) by A1;
consider V2 be Element of the entourages of US such that
A4: Y2 = Neighborhood(V2,x) by A2;
Y1 /\ Y2 = Neighborhood(V1 /\ V2,x) by A3,A4,Th11;
hence Y1 /\ Y2 in N;
end;
hence thesis by FINSUB_1:def 2;
end;
theorem Th18:
for US being non empty upper cap-closed axiom_U1 UniformSpaceStr,
x being Element of US holds
Neighborhood(x) is Filter of the carrier of US
proof
let US be non empty upper cap-closed axiom_U1 UniformSpaceStr,
x be Element of US;
set N = Neighborhood(x);
now
thus not {} in N
proof
assume {} in N;
then ex V be Element of the entourages of US st {} = Neighborhood(V,x);
hence thesis;
end;
hereby
let Y1,Y2 be Subset of US;
hereby
assume that
A1: Y1 in N and
A2: Y2 in N;
N is cap-closed by Th17;
hence Y1 /\ Y2 in N by A1,A2,FINSUB_1:def 2;
end;
hereby
assume that
A3: Y1 in N and
A4: Y1 c= Y2;
N is upper by Th15;
hence Y2 in N by A3,A4;
end;
end;
end;
hence thesis by CARD_FIL:def 1;
end;
registration
cluster -> topological for Locally-UniformSpace;
coherence
proof
let LUS be Locally-UniformSpace;
set UT = FMT_Space_Str(# the carrier of LUS,Neighborhood(LUS) #);
reconsider UT as non empty strict FMT_Space_Str;
A1: for x be Element of UT ex y be Element of LUS st
x = y & U_FMT x = Neighborhood(y)
proof
let x be Element of UT;
U_FMT x = (the BNbd of UT).x by FINTOPO2:def 6;
then consider y be Element of LUS such that
A2: x = y and
A3: U_FMT x = (Neighborhood(LUS)).y;
(Neighborhood(LUS)).y = Neighborhood(y) by Def5;
hence thesis by A2,A3;
end;
now
for x being Element of UT,V being Element of U_FMT x
ex W being Element of U_FMT x st for y being Element of UT st
y is Element of W holds V is Element of U_FMT y
proof
let x be Element of UT,V be Element of U_FMT x;
consider y be Element of LUS such that
x = y and
A4: U_FMT x = Neighborhood y by A1;
A5: V in Neighborhood y by A4;
then consider V0 be Element of the entourages of LUS such that
A6: V = Neighborhood(V0,y);
LUS is axiom_UL;
then consider W being Element of the entourages of LUS such that
A7: {z where z is Element of LUS: [y,z] in W * W} c=
Neighborhood(V0,y);
Neighborhood(W,y) in the set of all Neighborhood(V,y) where
V is Element of the entourages of LUS;
then reconsider WN = Neighborhood(W,y) as Element of Neighborhood y;
A8: for t,z be object st [y,t] in W & [t,z] in W holds [y,z] in V0
proof
let t,z be object;
assume that
A9: [y,t] in W and
A10: [t,z] in W;
consider R1,R2 being Relation of the carrier of LUS such that
A11: W = R1 and
A12: W = R2 and
W * W = R1 * R2;
AAA: [y,z] in R1 * R2 by A9,A10,A11,A12,RELAT_1:def 8;
consider a,b be object such that
a in the carrier of LUS and
A12B: b in the carrier of LUS and
A12C: [t,z] = [a,b] by A10,ZFMISC_1:def 2;
reconsider z as Element of LUS by A12C,A12B,XTUPLE_0:1;
z in {z where z is Element of LUS: [y,z] in W * W} by AAA,A11,A12;
then z in Neighborhood(V0,y) by A7;
then ex z0 be Element of LUS st z = z0 & [y,z0] in V0;
hence thesis;
end;
reconsider WN as Element of U_FMT x by A4;
take WN;
hereby
let z be Element of UT;
assume z is Element of WN;
then z in {z where z is Element of LUS: [y,z] in W};
then consider z0 be Element of LUS such that
A13: z = z0 and
A14: [y,z0] in W;
consider z1 be Element of LUS such that
A15: z = z1 and
A16: U_FMT z = Neighborhood z1 by A1;
A17: Neighborhood(W,z1) c= Neighborhood(V0,y)
proof
let t be object;
assume t in Neighborhood(W,z1);
then consider y0 be Element of LUS such that
A18: t = y0 and
A19: [z1,y0] in W;
[y,t] in V0 by A18,A19,A15,A13,A14,A8;
hence thesis by A18;
end;
Neighborhood(W,z1) in Neighborhood(z1);
then reconsider WW = Neighborhood(W,z1) as
Element of Neighborhood z1;
reconsider WW2 = WW,V2 = V as Subset of LUS by A5;
A20: WW2 c= V2 by A6,A17;
Neighborhood z1 is upper by Th15;
hence V is Element of U_FMT z by A16,A20;
end;
end;
hence UT is U_FMT_local;
for x being Element of UT, V being Element of U_FMT x holds x in V
proof
let x be Element of UT,V be Element of U_FMT x;
consider y be Element of LUS such that
A21: x = y and
A22: U_FMT x = Neighborhood y by A1;
V in the set of all Neighborhood(V,y) where
V is Element of the entourages of LUS by A22;
then ex W be Element of the entourages of LUS st V = Neighborhood(W,y);
hence thesis by A21,Th16;
end;
hence UT is U_FMT_with_point;
for x being Element of UT holds U_FMT x is Filter of the carrier of UT
proof
let x be Element of UT;
ex y be Element of LUS st x = y &
U_FMT x =Neighborhood y by A1;
hence thesis by Th18;
end;
hence UT is U_FMT_filter;
end;
hence thesis;
end;
end;
begin :: Topological Space induced by a Uniform Space Structure
definition
let USS be topological non empty axiom_U1 UniformSpaceStr;
func FMT_induced_by(USS) -> non empty strict FMT_TopSpace equals
FMT_Space_Str(# the carrier of USS,Neighborhood(USS) #);
coherence
proof
USS is topological;
hence thesis;
end;
end;
definition
let USS be topological non empty axiom_U1 UniformSpaceStr;
func TopSpace_induced_by(USS) -> TopSpace equals
FMT2TopSpace FMT_induced_by(USS);
coherence;
end;
begin :: The quasi-uniform Pervin Space induced by a topological space
definition
let X be set, A be Subset of X;
func block_Pervin_quasi_uniformity(A) -> Subset of [:X,X:] equals
[:X \ A,X:] \/ [:X,A:];
coherence
proof
A1: [:X \ A,X:] c= [:X,X:] by ZFMISC_1:95;
[:X,A:] c= [:X,X:] by ZFMISC_1:95;
hence thesis by A1,XBOOLE_1:8;
end;
end;
theorem Th20:
id X c= block_Pervin_quasi_uniformity(A) &
(block_Pervin_quasi_uniformity(A)) * (block_Pervin_quasi_uniformity(A))
c= block_Pervin_quasi_uniformity(A)
proof
thus id X c= block_Pervin_quasi_uniformity(A)
proof
let t be object;
assume
A1: t in id X;
then consider a,b be object such that
A2: t = [a,b] by RELAT_1:def 1;
A3: a in X & a = b by A1,A2,RELAT_1:def 10;
per cases;
suppose a in A;
then a in A & b in A by A1,A2,RELAT_1:def 10; then
A4: [a,b] in [:A,A:] by ZFMISC_1:def 2;
A5: [:A,A:] c= [:X,A:] by ZFMISC_1:96;
[:X,A:] c= block_Pervin_quasi_uniformity(A) by XBOOLE_1:7;
hence thesis by A4,A2,A5;
end;
suppose not a in A;
then a in X \ A by A3,XBOOLE_0:def 5; then
A6: t in [:X \ A,X:] by A2,A3,ZFMISC_1:def 2;
[:X \ A,X:] c= block_Pervin_quasi_uniformity(A) by XBOOLE_1:7;
hence thesis by A6;
end;
end;
now
let t be object;
assume
A7: t in (block_Pervin_quasi_uniformity(A)) *
(block_Pervin_quasi_uniformity(A));
then consider a,b be object such that
A8: t = [a,b] by RELAT_1:def 1;
[a,b] in {[x,y] where x,y is Element of X : ex z being Element of X st
[x,z] in block_Pervin_quasi_uniformity(A) &
[z,y] in block_Pervin_quasi_uniformity(A)} by A8,A7,Th3;
then consider x,y be Element of X such that
A9: [a,b] = [x,y] and
A10: ex z being Element of X st [x,z] in block_Pervin_quasi_uniformity(A)
& [z,y] in block_Pervin_quasi_uniformity(A);
consider z being Element of X such that
A11: [x,z] in block_Pervin_quasi_uniformity(A) and
A12: [z,y] in block_Pervin_quasi_uniformity(A) by A10;
per cases;
suppose
A13: x in A;
[x,z] in [:A,A:]
proof
per cases by A11,XBOOLE_0:def 3;
suppose [x,z] in [:X \ A,X:];
then x in X \ A by ZFMISC_1:87;
hence thesis by A13,XBOOLE_0:def 5;
end;
suppose [x,z] in [:X,A:];
then x in X & z in A by ZFMISC_1:87;
hence thesis by A13,ZFMISC_1:87;
end;
end;
then
A14: z in A by ZFMISC_1:87;
[z,y] in [:A,A:]
proof
per cases by A12,XBOOLE_0:def 3;
suppose [z,y] in [:X \ A,X:];
then z in X \ A & y in X by ZFMISC_1:87;
hence thesis by A14,XBOOLE_0:def 5;
end;
suppose [z,y] in [:X,A:];
then y in A by ZFMISC_1:87;
hence thesis by A14,ZFMISC_1:87;
end;
end;
then y in A by ZFMISC_1:87; then
A15: [x,y] in [:X,A:] by ZFMISC_1:def 2;
[:X,A:] c= block_Pervin_quasi_uniformity(A) by XBOOLE_1:7;
hence t in block_Pervin_quasi_uniformity(A) by A8,A9,A15;
end;
suppose
A16: not x in A;
per cases;
suppose
X is empty;
hence t in block_Pervin_quasi_uniformity(A) by A12;
end;
suppose
X is non empty;
then x in X \ A by A16,XBOOLE_0:def 5; then
A17: t in [:X \ A,X:] by A8,A9,ZFMISC_1:87;
[:X \ A,X:] c= block_Pervin_quasi_uniformity(A) by XBOOLE_1:7;
hence t in block_Pervin_quasi_uniformity(A) by A17;
end;
end;
end;
hence thesis;
end;
definition
let T be TopSpace;
func subbasis_Pervin_quasi_uniformity(T) ->
Subset-Family of [:the carrier of T,the carrier of T:] equals
the set of all block_Pervin_quasi_uniformity(O) where
O is Element of the topology of T;
coherence
proof
the set of all block_Pervin_quasi_uniformity(O) where
O is Element of the topology of T
c= bool [:the carrier of T,the carrier of T:]
proof
let x be object;
assume x in the set of all block_Pervin_quasi_uniformity(O) where
O is Element of the topology of T;
then ex O be Element of the topology of T st
x = block_Pervin_quasi_uniformity(O);
hence thesis;
end;
hence thesis;
end;
end;
registration
let T be non empty TopSpace;
cluster subbasis_Pervin_quasi_uniformity(T) -> non empty;
coherence
proof
block_Pervin_quasi_uniformity(the Element of the topology of T)
in subbasis_Pervin_quasi_uniformity(T);
hence thesis;
end;
end;
definition
let T be TopSpace;
func basis_Pervin_quasi_uniformity(T) -> Subset-Family of
[:the carrier of T,the carrier of T:] equals
FinMeetCl(subbasis_Pervin_quasi_uniformity(T));
coherence;
end;
registration
let X be set;
cluster cap-closed -> quasi_basis for non empty Subset-Family of [:X,X:];
coherence
proof
let SF be non empty Subset-Family of [:X,X:];
assume
A1: SF is cap-closed;
now
let b1,b2 be Element of SF;
b1 /\ b2 in SF by A1,FINSUB_1:def 2;
hence ex b be Element of SF st b c= b1/\b2;
end;
hence thesis;
end;
end;
reserve T for TopSpace;
registration
let T;
cluster basis_Pervin_quasi_uniformity(T) -> cap-closed;
coherence
proof
now
let x,y be set;
assume that
A1: x in basis_Pervin_quasi_uniformity(T) and
A2: y in basis_Pervin_quasi_uniformity(T);
consider Y being Subset-Family of
[:the carrier of T,the carrier of T:] such that
A3: Y c= subbasis_Pervin_quasi_uniformity(T) and
A4: Y is finite and
A5: x = Intersect Y by A1,CANTOR_1:def 3;
consider Z being Subset-Family of
[:the carrier of T,the carrier of T:] such that
A6: Z c= subbasis_Pervin_quasi_uniformity(T) and
A7: Z is finite and
A8: y = Intersect Z by A2,CANTOR_1:def 3;
A9: x /\ y = Intersect (Y \/ Z) by A5,A8,MSSUBFAM:8;
Y \/ Z c= subbasis_Pervin_quasi_uniformity(T) by A3,A6,XBOOLE_1:8;
hence x /\ y in basis_Pervin_quasi_uniformity(T)
by A9,A4,A7,CANTOR_1:def 3;
end;
hence thesis by FINSUB_1:def 2;
end;
end;
registration
let T;
cluster basis_Pervin_quasi_uniformity(T) -> quasi_basis;
coherence;
end;
registration
let T;
cluster basis_Pervin_quasi_uniformity(T) -> axiom_UP1;
coherence
proof
let B be Element of basis_Pervin_quasi_uniformity(T);
B in FinMeetCl(subbasis_Pervin_quasi_uniformity(T));
then consider Y being Subset-Family of
[:the carrier of T,the carrier of T:] such that
A1: Y c= subbasis_Pervin_quasi_uniformity(T) and
Y is finite and
A2: B = Intersect Y by CANTOR_1:def 3;
let t be object;
assume
A3: t in id the carrier of T;
then consider a,b be object such that
A4: t = [a,b] by RELAT_1:def 1;
A5: a in the carrier of T & a = b by A3,A4,RELAT_1:def 10;
per cases;
suppose Y is empty;
then B = [:the carrier of T,the carrier of T:] by A2,SETFAM_1:def 9;
hence thesis by A3;
end;
suppose
A7: Y is non empty; then
A8: Intersect Y = meet Y by SETFAM_1:def 9;
now
let y be set;
assume y in Y;
then y in the set of all block_Pervin_quasi_uniformity(O) where
O is Element of the topology of T by A1;
then consider O be Element of the topology of T such that
A9: y = block_Pervin_quasi_uniformity(O);
A10: [:(the carrier of T) \ O,the carrier of T:] c= y &
[:the carrier of T,O:] c= y by A9,XBOOLE_1:10;
per cases by A5,XBOOLE_0:def 5;
suppose a in (the carrier of T) \ O;
then [a,b] in [:(the carrier of T) \ O,the carrier of T:]
by A5,ZFMISC_1:def 2;
hence t in y by A4,A10;
end;
suppose a in O;
then [a,b] in [:the carrier of T,O:] by A5,ZFMISC_1:def 2;
hence t in y by A4,A10;
end;
end;
hence thesis by A2,A8,A7,SETFAM_1:def 1;
end;
end;
end;
registration
let T;
cluster basis_Pervin_quasi_uniformity(T) -> axiom_UP3;
coherence
proof
let B1 be Element of basis_Pervin_quasi_uniformity(T);
B1 in FinMeetCl(subbasis_Pervin_quasi_uniformity(T));
then consider Y being Subset-Family of
[:the carrier of T,the carrier of T:] such that
A1: Y c= subbasis_Pervin_quasi_uniformity(T) and
Y is finite and
A2: B1 = Intersect Y by CANTOR_1:def 3;
per cases;
suppose Y is empty; then
A3: B1 = [:the carrier of T,the carrier of T:] by A2,SETFAM_1:def 9;
take B1;
thus thesis by A3;
end;
suppose
A4: Y is non empty; then
A5: B1 = meet Y by A2,SETFAM_1:def 9;
reconsider B2 = B1 as Element of basis_Pervin_quasi_uniformity(T);
take B2;
let t be object;
assume
A6: t in B2 * B2;
consider a,b be object such that
A10: t = [a,b] by A6,RELAT_1:def 1;
consider c be object such that
A11: [a,c] in B2 and
A12: [c,b] in B2 by A6,A10,RELAT_1:def 8;
thus t in B1
proof
for Z be set st Z in Y holds t in Z
proof
let Z be set;
assume
A13: Z in Y;
then Z in the set of all block_Pervin_quasi_uniformity(O)
where O is Element of the topology of T by A1;
then consider O be Element of the topology of T such that
A14: Z = block_Pervin_quasi_uniformity(O);
[a,c] in meet Y by A4,A2,SETFAM_1:def 9,A11; then
A15: [a,c] in block_Pervin_quasi_uniformity(O)
by A14,A13,SETFAM_1:def 1;
[c,b] in block_Pervin_quasi_uniformity(O)
by A12,A5,A14,A13,SETFAM_1:def 1; then
A16: [a,b] in (block_Pervin_quasi_uniformity(O)) *
(block_Pervin_quasi_uniformity(O)) by A15,RELAT_1:def 8;
(block_Pervin_quasi_uniformity(O)) *
(block_Pervin_quasi_uniformity(O)) c=
block_Pervin_quasi_uniformity(O) by Th20;
hence thesis by A14,A10,A16;
end;
hence thesis by A5,A4,SETFAM_1:def 1;
end;
end;
end;
end;
definition
let T be TopSpace;
func Pervin_quasi_uniformity T -> strict Quasi-UniformSpace equals
UniformSpaceStr(# the carrier of T,<.basis_Pervin_quasi_uniformity(T).] #);
coherence by Th11bis;
end;
theorem
for T being non empty TopSpace, V being Element of the entourages of
Pervin_quasi_uniformity T ex b being Element of
FinMeetCl(subbasis_Pervin_quasi_uniformity(T)) st b c= V
proof
let T be non empty TopSpace, V be Element of the entourages of
Pervin_quasi_uniformity T;
A1: <.basis_Pervin_quasi_uniformity(T).] = {x where x is Subset of
[:the carrier of T,the carrier of T:]: ex b be Element of
basis_Pervin_quasi_uniformity(T) st b c= x} by CARDFIL2:14;
V in <.basis_Pervin_quasi_uniformity(T).];
then ex S be Subset of [:the carrier of T,the carrier of T:] st V = S &
ex b be Element of basis_Pervin_quasi_uniformity(T) st b c= S by A1;
hence thesis;
end;
theorem
for T being non empty TopSpace, V being Subset of
[:the carrier of T,the carrier of T:] st ex b being Element of
FinMeetCl(subbasis_Pervin_quasi_uniformity(T)) st b c= V
holds V is Element of the entourages of Pervin_quasi_uniformity T
proof
let T be non empty TopSpace, V be Subset of
[:the carrier of T,the carrier of T:];
given b being Element of FinMeetCl(subbasis_Pervin_quasi_uniformity(T))
such that
A1: b c= V;
A2: <.basis_Pervin_quasi_uniformity(T).] = {x where x is Subset of
[:the carrier of T,the carrier of T:]:
ex b be Element of basis_Pervin_quasi_uniformity(T) st b c= x}
by CARDFIL2:14;
V in <.basis_Pervin_quasi_uniformity(T).] by A1,A2;
hence thesis;
end;
theorem
subbasis_Pervin_quasi_uniformity(T) c=
the entourages of Pervin_quasi_uniformity T
proof
now
let x be object;
assume
A1: x in subbasis_Pervin_quasi_uniformity(T);
A2: subbasis_Pervin_quasi_uniformity(T) c=
basis_Pervin_quasi_uniformity(T) by CANTOR_1:4;
basis_Pervin_quasi_uniformity(T) c= <.basis_Pervin_quasi_uniformity(T).]
by CARDFIL2:18;
hence x in the entourages of Pervin_quasi_uniformity T by A1,A2;
end;
hence thesis;
end;
theorem Th27:
for QU being non void Quasi-UniformSpace holds
[:the carrier of QU,the carrier of QU:] in the entourages of QU
proof
let QU be non void Quasi-UniformSpace;
A1: QU is non void;
set U = the Element of the entourages of QU;
U in the entourages of QU by A1;
then reconsider U as Subset of [:the carrier of QU,the carrier of QU:];
QU is upper; then
A2: the entourages of QU is upper;
[:the carrier of QU,the carrier of QU:] c=
[:the carrier of QU,the carrier of QU:];
then reconsider Y = [:the carrier of QU,the carrier of QU:] as
Subset of [:the carrier of QU,the carrier of QU:];
the entourages of QU is non empty by A1;
then Y in the entourages of QU by A2;
hence thesis;
end;
theorem
for QU being non void Quasi-UniformSpace st
the carrier of T = the carrier of QU &
subbasis_Pervin_quasi_uniformity(T) c= the entourages of QU
holds the entourages of Pervin_quasi_uniformity T c= the entourages of QU
proof
let QU be non void Quasi-UniformSpace;
assume that
A2: the carrier of T = the carrier of QU and
A3: subbasis_Pervin_quasi_uniformity(T) c= the entourages of QU;
the entourages of Pervin_quasi_uniformity T c= the entourages of QU
proof
let x be object;
assume
A4: x in the entourages of Pervin_quasi_uniformity T;
then reconsider y = x as Subset of [:the carrier of T,the carrier of T:];
consider b be Element of basis_Pervin_quasi_uniformity(T) such that
A5: b c= y by A4,CARDFIL2:def 8;
b in FinMeetCl(subbasis_Pervin_quasi_uniformity(T));
then consider Y be Subset-Family of
[:the carrier of T,the carrier of T:] such that
A6: Y c= subbasis_Pervin_quasi_uniformity(T) and
A7: Y is finite and
A8: b = Intersect Y by CANTOR_1:def 3;
reconsider Z = Y as finite Subset-Family of
[:the carrier of QU,the carrier of QU:] by A2,A7;
reconsider B = the entourages of QU as set;
A9: now
thus B is Subset-Family of [:the carrier of QU,the carrier of QU:];
QU is cap-closed;
hence B is cap-closed;
thus [:the carrier of QU,the carrier of QU:] in B by Th27;
thus Z c= B by A3,A6;
end;
QU is upper; then
A10: the entourages of QU is upper;
b is Subset of [:the carrier of QU,the carrier of QU:] &
y is Subset of [:the carrier of QU,the carrier of QU:] & b c= y &
b in the entourages of QU by A5,A9,A2,A8,ARMSTRNG:1;
hence thesis by A10;
end;
hence thesis;
end;
registration
let T be non empty TopSpace;
cluster Pervin_quasi_uniformity T -> non empty;
coherence;
end;
registration
let T be non empty TopSpace;
cluster Pervin_quasi_uniformity T -> topological;
coherence
proof
set US = Pervin_quasi_uniformity T,
FMT = FMT_Space_Str(# the carrier of Pervin_quasi_uniformity T,
Neighborhood(Pervin_quasi_uniformity T) #);
reconsider UT = FMT as non empty strict FMT_Space_Str;
A1: for x be Element of UT ex y be Element of US st
x = y & U_FMT x = Neighborhood(y)
proof
let x be Element of UT;
U_FMT x = (the BNbd of UT).x by FINTOPO2:def 6;
then consider y be Element of US such that
A2: x = y and
A3: U_FMT x = (Neighborhood(US)).y;
(Neighborhood(US)).y = Neighborhood(y) by Def5;
hence thesis by A2,A3;
end;
now
for x being Element of UT,V being Element of U_FMT x
ex W being Element of U_FMT x st for y being Element of UT st
y is Element of W holds V is Element of U_FMT y
proof
let x be Element of UT,V be Element of U_FMT x;
consider y be Element of US such that
x = y and
A4: U_FMT x = Neighborhood y by A1;
A5: V in Neighborhood y by A4;
then consider V0 be Element of the entourages of US such that
A6: V = Neighborhood(V0,y);
US is axiom_U3;
then consider W be Element of the entourages of US such that
A7: W * W c= V0;
Neighborhood(W,y) in the set of all Neighborhood(V,y) where
V is Element of the entourages of US;
then reconsider WN = Neighborhood(W,y) as Element of Neighborhood y;
A8: for x,y,z be object st [x,y] in W & [y,z] in W holds [x,z] in V0
proof
let x,y,z be object;
assume that
A9: [x,y] in W and
A10: [y,z] in W;
[x,z] in W * W by A9,A10,RELAT_1:def 8;
hence thesis by A7;
end;
reconsider WN as Element of U_FMT x by A4;
take WN;
hereby
let z be Element of UT;
assume z is Element of WN;
then z in {z where z is Element of US: [y,z] in W};
then consider z0 be Element of US such that
A13: z = z0 and
A14: [y,z0] in W;
consider z1 be Element of US such that
A15: z = z1 and
A16: U_FMT z = Neighborhood z1 by A1;
A17: Neighborhood(W,z1) c= Neighborhood(V0,y)
proof
let t be object;
assume t in Neighborhood(W,z1);
then consider y0 be Element of US such that
A18: t = y0 and
A19: [z1,y0] in W;
[y,t] in V0 by A18,A19,A15,A13,A14,A8;
hence thesis by A18;
end;
Neighborhood(W,z1) in Neighborhood(z1);
then reconsider WW = Neighborhood(W,z1) as
Element of Neighborhood z1;
reconsider WW2 = WW,V2 = V as Subset of US by A5;
A20: WW2 c= V2 by A6,A17;
Neighborhood z1 is upper by Th15;
hence V is Element of U_FMT z by A16,A20;
end;
end;
hence UT is U_FMT_local;
for x being Element of UT, V being Element of U_FMT x holds x in V
proof
let x be Element of UT,V be Element of U_FMT x;
consider y be Element of US such that
A21: x = y and
A22: U_FMT x = Neighborhood y by A1;
V in the set of all Neighborhood(V,y) where
V is Element of the entourages of US by A22;
then ex W be Element of the entourages of US st V = Neighborhood(W,y);
hence thesis by A21,Th16;
end;
hence UT is U_FMT_with_point;
for x being Element of UT holds U_FMT x is Filter of the carrier of UT
proof
let x be Element of UT;
ex y be Element of US st x = y & U_FMT x =Neighborhood y by A1;
hence thesis by Th18;
end;
hence UT is U_FMT_filter;
end;
hence thesis;
end;
end;
theorem Th29:
for T being non empty TopSpace, x being Element of
subbasis_Pervin_quasi_uniformity(T),
y being Element of Pervin_quasi_uniformity T holds
{z where z is Element of Pervin_quasi_uniformity T:
[y,z] in x} in the topology of T
proof
let T be non empty TopSpace, x be Element of
subbasis_Pervin_quasi_uniformity(T),
y be Element of Pervin_quasi_uniformity T;
x in subbasis_Pervin_quasi_uniformity(T);
then consider O be Element of the topology of T such that
A1: x = block_Pervin_quasi_uniformity(O);
set M = {z where z is Element of Pervin_quasi_uniformity T:
[y,z] in x};
per cases;
suppose
A2: y in O;
M = O
proof
thus M c= O
proof
let a be object;
assume a in M;
then consider b be Element of
Pervin_quasi_uniformity T such that
A4: b = a and
A5: [y,b] in x;
[y,b] in [:(the carrier of T) \ O,the carrier of T:] or
[y,b] in [:the carrier of T,O:] by A1,A5,XBOOLE_0:def 3;
then (y in (the carrier of T) \ O & b in the carrier of T) or
(y in the carrier of T & b in O) by ZFMISC_1:87;
hence thesis by A4,A2,XBOOLE_0:def 5;
end;
let a be object;
assume
A6: a in O;
then reconsider b = a as Element of
Pervin_quasi_uniformity T;
[y,b] in [:the carrier of T,O:] by A6,ZFMISC_1:87;
then [y,b] in [:(the carrier of T) \ O,the carrier of T:] \/
[:the carrier of T,O:] by XBOOLE_0:def 3;
hence thesis by A1;
end;
hence thesis;
end;
suppose
A7: not y in O;
M = the carrier of Pervin_quasi_uniformity T
proof
thus M c= the carrier of Pervin_quasi_uniformity T
proof
let a be object;
assume a in M;
then ex b be Element of Pervin_quasi_uniformity T st
a = b & [y,b] in x;
hence thesis;
end;
let a be object;
assume a in the carrier of Pervin_quasi_uniformity T;
then reconsider b = a as Element of the carrier of
Pervin_quasi_uniformity T;
y in (the carrier of T) \ O & b in the carrier of T
by A7,XBOOLE_0:def 5; then
A10: [y,b] in [:(the carrier of T) \ O, the carrier of T:] by ZFMISC_1:87;
[:(the carrier of T) \ O, the carrier of T:] c=
[:(the carrier of T) \ O, the carrier of T:] \/
[:the carrier of T,O:] by XBOOLE_1:7;
hence thesis by A1,A10;
end;
hence thesis by PRE_TOPC:def 1;
end;
end;
theorem Th30:
for T being non empty TopSpace,x being Element of the carrier of
Pervin_quasi_uniformity T, b being Element of
FinMeetCl(subbasis_Pervin_quasi_uniformity(T)) holds
{y where y is Element of T:[x,y] in b} in the topology of T
proof
let T be non empty TopSpace, x be Element of the carrier of
Pervin_quasi_uniformity T, b be Element of
FinMeetCl(subbasis_Pervin_quasi_uniformity(T));
consider Y being Subset-Family of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:] such that
A1: Y c= subbasis_Pervin_quasi_uniformity(T) and
A2: Y is finite and
A3: b = Intersect Y by CANTOR_1:def 3;
per cases;
suppose Y is empty;
then
A4: b = [:the carrier of T,the carrier of T:] by A3,SETFAM_1:def 9;
{y where y is Element of T:[x,y] in b} = the carrier of T
proof
thus {y where y is Element of T:[x,y] in b} c=
the carrier of T
proof
let a be object;
assume a in {y where y is Element of T:[x,y] in b};
then ex y be Element of T st a = y & [x,y] in b;
hence thesis;
end;
let a be object;
assume a in the carrier of T;
then reconsider y = a as Element of T;
[x,y] in [:the carrier of T,the carrier of T:];
hence thesis by A4;
end;
hence thesis by PRE_TOPC:def 1;
end;
suppose
A7: Y is non empty; then
A8: b = meet Y by A3,SETFAM_1:def 9;
for Y be non empty Subset-Family of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:] st Y c=
subbasis_Pervin_quasi_uniformity(T) & Y is finite
holds {y where y is Element of T:[x,y] in meet Y}
in the topology of T
proof
let Y be non empty Subset-Family of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:];
assume that
A9: Y c= subbasis_Pervin_quasi_uniformity(T) and
A10: Y is finite;
defpred P[Nat] means for Z be non empty Subset-Family of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:] st
Z c= subbasis_Pervin_quasi_uniformity(T) &
card Z = $1 holds {y where y is Element of T:[x,y]
in meet Z} in the topology of T;
for Z be non empty Subset-Family of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:] st
Z c= subbasis_Pervin_quasi_uniformity(T) &
card Z = 1 holds {y where y is Element of T:[x,y]
in meet Z} in the topology of T
proof
let Z be non empty Subset-Family of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:];
assume that
A11: Z c= subbasis_Pervin_quasi_uniformity(T) and
A12: card Z = 1;
consider t be object such that
A13: Z = {t} by A12,CARD_2:42;
reconsider y = t as set by TARSKI:1;
A14: meet Z = y by A13,SETFAM_1:10;
t in subbasis_Pervin_quasi_uniformity(T) by A11,A13,ZFMISC_1:31;
then consider O be Element of the topology of T such that
A15: t = block_Pervin_quasi_uniformity(O);
per cases;
suppose
A16: x in O;
{y where y is Element of T:[x,y] in meet Z}
in the topology of T
proof
A17: {z where z is Element of T:[x,z] in
block_Pervin_quasi_uniformity(O)} = O
proof
A18: {z where z is Element of T:[x,z] in
block_Pervin_quasi_uniformity(O)} c= O
proof
let a be object;
assume a in {z where z is Element of T:
[x,z] in block_Pervin_quasi_uniformity(O)};
then ex z be Element of T st a = z &
[x,z] in block_Pervin_quasi_uniformity(O);
then [x,a] in [:(the carrier of T) \ O,the carrier of T:] or
[x,a] in [:the carrier of T,O:] by XBOOLE_0:def 3;
then (x in (the carrier of T) \ O & a in the carrier of T)
or (x in the carrier of T & a in O) by ZFMISC_1:87;
hence thesis by A16,XBOOLE_0:def 5;
end;
O c= {z where z is Element of T:[x,z]
in block_Pervin_quasi_uniformity(O)}
proof
let a be object;
assume
A19: a in O;
then reconsider b = a as Element of T;
[x,a] in [:the carrier of T,O:] by A19,ZFMISC_1:87;
then [x,b] in block_Pervin_quasi_uniformity(O)
by XBOOLE_0:def 3;
hence thesis;
end;
hence thesis by A18;
end;
thus thesis by A15,A14,A17;
end;
hence thesis;
end;
suppose
A20: not x in O;
{z where z is Element of T:[x,z] in
block_Pervin_quasi_uniformity(O)} = the carrier of T
proof
thus {z where z is Element of T:[x,z] in
block_Pervin_quasi_uniformity(O)} c= the carrier of T
proof
let a be object;
assume a in {z where z is Element of T:
[x,z] in block_Pervin_quasi_uniformity(O)};
then ex z be Element of T st a = z & [x,z]
in block_Pervin_quasi_uniformity(O);
hence thesis;
end;
let a be object;
assume a in the carrier of T;
then reconsider b = a as Element of T;
x in (the carrier of T)\O by A20,XBOOLE_0:def 5;
then [x,b] in [:(the carrier of T) \ O,the carrier of T:] or
[x,b] in [:the carrier of T,O:] by ZFMISC_1:87;
then [x,b] in block_Pervin_quasi_uniformity(O)
by XBOOLE_0:def 3;
hence thesis;
end;
hence thesis by A15,A14,PRE_TOPC:def 1;
end;
end;
then
A22: P[1];
A23: for k being non zero Nat st P[k] holds P[k+1]
proof
let k be non zero Nat;
assume
A24: P[k];
now
let Z be non empty Subset-Family of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:];
assume that
A25: Z c= subbasis_Pervin_quasi_uniformity(T) and
A26: card Z = k + 1;
set z = the Element of Z;
A27: card (Z \ {z}) = k by A26,STIRL2_1:55; then
A28: Z \ {z} is non empty;
Z \ {z} c= Z by XBOOLE_1:36; then
A29: Z \ {z} c= subbasis_Pervin_quasi_uniformity(T) by A25;
Z \ {z} is non empty Subset-Family of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:] by A27; then
A30: {y where y is Element of T:[x,y] in
meet (Z \ {z})} in the topology of T by A24,A27,A29;
A31: {y where y is Element of T:[x,y] in
meet (Z \ {z})} /\ {y where y is Element of T:
[x,y] in z}
= {y where y is Element of T:[x,y] in meet Z}
proof
set M1 = {y where y is Element of T:[x,y] in
meet (Z \ {z})},
M2 = {y where y is Element of T:[x,y] in z},
M3 = {y where y is Element of T:[x,y] in
meet Z};
A32: M1 /\ M2 c= M3
proof
let a be object;
assume a in M1 /\ M2;then
A33: a in M1 & a in M2 by XBOOLE_0:def 4;
then consider b be Element of T such that
A34: a = b and
A35: [x,b] in meet(Z \ {z});
consider c be Element of T such that
A36: a = c and
A37: [x,c] in z by A33;
now
let Y be set;
assume Y in Z;
then per cases;
suppose Y in Z & not Y in {z};
then Y in Z \{z} by XBOOLE_0:def 5;
hence [x,b] in Y by A35,SETFAM_1:def 1;
end;
suppose Y in {z};
hence [x,b] in Y by A34,A36,A37,TARSKI:def 1;
end;
end;
then [x,b] in meet Z by SETFAM_1:def 1;
hence thesis by A34;
end;
M3 c= M1 /\ M2
proof
let a be object;
assume a in M3;
then consider b be Element of T such that
A38: a = b and
A39: [x,b] in meet Z;
now
let Y be set;
assume
A40: Y in Z \ {z};
Z \ {z} c= Z by XBOOLE_1:36;
hence [x,b] in Y by A40,A39,SETFAM_1:def 1;
end;
then [x,b] in meet (Z \ {z}) by A28,SETFAM_1:def 1; then
A41: b in M1;
[x,b] in z by A39,SETFAM_1:def 1;
then a in M2 by A38;
hence thesis by A41,A38,XBOOLE_0:def 4;
end;
hence thesis by A32;
end;
z in subbasis_Pervin_quasi_uniformity(T) by A25;
then {y where y is Element of T:[x,y] in z} in
the topology of T by Th29;
hence {y where y is Element of T:[x,y] in meet Z}
in the topology of T by A31,A30,PRE_TOPC:def 1;
end;
hence thesis;
end;
A42: for k being non zero Nat holds P[k] from NAT_1:sch 10(A22,A23);
ex n be Nat st card Y = n by A10;
hence thesis by A9,A42;
end;
hence thesis by A8,A1,A2,A7;
end;
end;
theorem Th31:
for UT being non empty strict Quasi-UniformSpace,
FMT being non empty strict FMT_Space_Str, x being Element of FMT st
FMT = FMT_Space_Str(#the carrier of UT,Neighborhood(UT) #) holds
ex y being Element of UT st x = y &
U_FMT x = Neighborhood y
proof
let UT be non empty strict Quasi-UniformSpace,
FMT be non empty strict FMT_Space_Str,
x be Element of FMT;
assume
A1: FMT = FMT_Space_Str(#the carrier of UT,Neighborhood(UT) #);
U_FMT x = (the BNbd of FMT).x by FINTOPO2:def 6;
then consider y be Element of UT such that
A2: x = y and
A3: U_FMT x = (Neighborhood(UT)).y by A1;
(Neighborhood(UT)).y = Neighborhood(y) by Def5;
hence thesis by A2,A3;
end;
theorem Th32:
for T being non empty TopSpace holds
Family_open_set(FMT_induced_by(Pervin_quasi_uniformity T)) =
the topology of T
proof
let T be non empty TopSpace;
A1: Family_open_set(FMT_induced_by(Pervin_quasi_uniformity T)) c=
the topology of T
proof
let x be object;
assume x in Family_open_set(FMT_induced_by(Pervin_quasi_uniformity T));
then consider O be open Subset of
FMT_induced_by(Pervin_quasi_uniformity T) such that
A2: x = O;
reconsider O1 = O as Subset of T;
for x be set holds x in O1 iff ex B be Subset of T st
B is open & B c= O1 & x in B
proof
let x be set;
hereby
assume
A3: x in O1;
then reconsider t = x as Element of
FMT_induced_by(Pervin_quasi_uniformity T);
consider y being Element of the carrier of
Pervin_quasi_uniformity T such that
A4: t = y and
A5: U_FMT t = Neighborhood y by Th31;
O in Neighborhood y by A5,FINTOPO7:def 1,A3;
then consider V be Element of the entourages of
Pervin_quasi_uniformity T such that
A6: O = Neighborhood(V,y);
consider b be Element of
FinMeetCl(subbasis_Pervin_quasi_uniformity(T)) such that
A7: b c= V by CARDFIL2:def 8;
FinMeetCl(subbasis_Pervin_quasi_uniformity(T)) c=
<.FinMeetCl(subbasis_Pervin_quasi_uniformity(T)).]
by CARDFIL2:18; then
A16: b in the entourages of Pervin_quasi_uniformity T;
A17: [y,y] in id the carrier of Pervin_quasi_uniformity T
by RELAT_1:def 10;
Pervin_quasi_uniformity T is axiom_U1; then
A18: id the carrier of Pervin_quasi_uniformity T c= b by A16;
reconsider B = {z where z is Element of the carrier of
Pervin_quasi_uniformity T:
[y,z] in b} as set;
B c= the carrier of Pervin_quasi_uniformity T
proof
let t be object;
assume t in B;
then ex z be Element of T st t = z & [y,z] in b;
hence thesis;
end;
then reconsider B as Subset of T;
now
take B;
thus B is open by Th30,PRE_TOPC:def 2;
B c= O
proof
let t be object;
assume t in B;
then ex z be Element of T st t = z & [y,z] in b;
hence thesis by A7,A6;
end;
hence B c= O1;
thus x in B by A4,A18,A17;
end;
hence ex B be Subset of T st B is open & B c= O1 &
x in B;
end;
assume ex B be Subset of T st B is open & B c= O1 &
x in B;
hence x in O1;
end;
hence thesis by A2,PRE_TOPC:def 2,TOPS_1:25;
end;
the topology of T c=
Family_open_set(FMT_induced_by(Pervin_quasi_uniformity T))
proof
let x be object;
assume
A20: x in the topology of T;
then reconsider y = x as Subset of T;
reconsider z = y as Subset of Pervin_quasi_uniformity T;
for u be Element of FMT_induced_by(Pervin_quasi_uniformity T) st
u in z holds z in U_FMT u
proof
let u be Element of FMT_induced_by(Pervin_quasi_uniformity T);
assume
A21: u in z;
consider w being Element of the carrier of
Pervin_quasi_uniformity T such that
A22: u = w and
A23: U_FMT u = Neighborhood w by Th31;
reconsider W = block_Pervin_quasi_uniformity(y) as Subset of
[:the carrier of Pervin_quasi_uniformity T,
the carrier of Pervin_quasi_uniformity T:];
A24: W in subbasis_Pervin_quasi_uniformity(T) by A20;
A25: subbasis_Pervin_quasi_uniformity(T) c=
FinMeetCl(subbasis_Pervin_quasi_uniformity(T)) by CANTOR_1:4;
FinMeetCl(subbasis_Pervin_quasi_uniformity(T)) c=
<.FinMeetCl(subbasis_Pervin_quasi_uniformity(T)).] by CARDFIL2:18;
then reconsider W as Element of the entourages of
Pervin_quasi_uniformity T by A25,A24;
{ww where ww is Element of T: [w,ww] in
block_Pervin_quasi_uniformity(y)} = y
proof
thus {ww where ww is Element of T: [w,ww] in
block_Pervin_quasi_uniformity(y)} c= y
proof
let a be object;
assume a in {ww where ww is Element of T:
[w,ww] in block_Pervin_quasi_uniformity(y)};
then consider ww be Element of T such that
A27: a = ww and
A28: [w,ww] in [:(the carrier of T) \ y,the carrier of T:] \/
[:the carrier of T,y:];
[w,ww] in [:(the carrier of T) \ y,the carrier of T:] or
[w,ww] in [:the carrier of T,y:] by A28,XBOOLE_0:def 3;
then (w in (the carrier of T) \ y & ww in the carrier of T) or
(w in the carrier of T & ww in y) by ZFMISC_1:87;
hence thesis by A27,A21,A22,XBOOLE_0:def 5;
end;
let a be object;
assume
A29: a in y;
then reconsider b = a as Element of T;
[w,b] in [:the carrier of T,y:] by A29,ZFMISC_1:87;
then [w,b] in block_Pervin_quasi_uniformity(y) by XBOOLE_0:def 3;
hence thesis;
end;
then z = Neighborhood(W,w);
hence thesis by A23;
end;
then z is open Subset of FMT_induced_by(Pervin_quasi_uniformity T)
by FINTOPO7:def 1;
hence thesis;
end;
hence thesis by A1;
end;
theorem
for T being non empty strict TopSpace holds
TopSpace_induced_by(Pervin_quasi_uniformity T) = T
proof
let T be non empty strict TopSpace;
the topology of TopSpace_induced_by(Pervin_quasi_uniformity T)
= Family_open_set(FMT_induced_by(Pervin_quasi_uniformity T))
by FINTOPO7:def 16;
hence thesis by FINTOPO7:def 16,Th32;
end;