:: Auxiliary and Approximating Relations
:: by Adam Grabowski
::
:: Received October 21, 1996
:: Copyright (c) 1996-2018 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 XBOOLE_0, RELAT_2, ORDERS_2, RELAT_1, SUBSET_1, WAYBEL_3,
STRUCT_0, XXREAL_0, EQREL_1, LATTICES, LATTICE3, WAYBEL_0, TARSKI,
ZFMISC_1, YELLOW_1, SETFAM_1, REWRITE1, YELLOW_0, FUNCT_1, CARD_FIL,
SEQM_3, PARTFUN1, CAT_1, NEWTON, FUNCOP_1, FUNCT_2, CARD_3, RLVECT_2,
WELLORD1, YELLOW_2, WELLORD2, ORDINAL2, WAYBEL_2, ARYTM_3, ORDERS_1,
WAYBEL_4;
notations TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, SETFAM_1, RELAT_1, RELAT_2,
FUNCT_1, RELSET_1, PARTFUN1, FUNCT_2, DOMAIN_1, ORDERS_1, STRUCT_0,
ORDERS_2, LATTICE3, WELLORD1, YELLOW_0, FUNCOP_1, CARD_3, PRALG_1,
YELLOW_1, ALG_1, YELLOW_2, YELLOW_4, WAYBEL_0, WAYBEL_1, WAYBEL_2,
WAYBEL_3;
constructors SETFAM_1, DOMAIN_1, TOLER_1, PRALG_1, ORDERS_3, WAYBEL_1,
YELLOW_4, WAYBEL_2, WAYBEL_3, RELSET_1;
registrations SUBSET_1, RELAT_1, FUNCT_1, FUNCT_2, STRUCT_0, LATTICE3,
YELLOW_0, WAYBEL_0, YELLOW_1, YELLOW_2, WAYBEL_2, WAYBEL_3, FUNCOP_1;
requirements SUBSET, BOOLE;
begin :: Auxiliary Relations
definition
let L be non empty reflexive RelStr;
func L-waybelow -> Relation of L means
:: WAYBEL_4:def 1
for x,y being Element of L holds [x,y] in it iff x << y;
end;
definition
let L be RelStr;
func IntRel L -> Relation of L equals
:: WAYBEL_4:def 2
the InternalRel of L;
end;
definition
let L be RelStr, R be Relation of L;
attr R is auxiliary(i) means
:: WAYBEL_4:def 3
for x, y being Element of L holds [x,y] in R implies x <= y;
attr R is auxiliary(ii) means
:: WAYBEL_4:def 4
for x, y, z, u being Element of L holds
( u <= x & [x,y] in R & y <= z implies [u,z] in R );
end;
definition
let L be non empty RelStr, R be Relation of L;
attr R is auxiliary(iii) means
:: WAYBEL_4:def 5
for x, y, z being Element of L holds
( [x,z] in R & [y,z] in R implies [(x "\/" y),z] in R );
attr R is auxiliary(iv) means
:: WAYBEL_4:def 6
for x being Element of L holds [Bottom L,x] in R;
end;
:: Definition 1.9 p.43
definition
let L be non empty RelStr, R be Relation of L;
attr R is auxiliary means
:: WAYBEL_4:def 7
R is auxiliary(i) auxiliary(ii) auxiliary(iii) auxiliary(iv);
end;
registration
let L be non empty RelStr;
cluster auxiliary ->
auxiliary(i) auxiliary(ii) auxiliary(iii) auxiliary(iv) for Relation of L;
cluster auxiliary(i) auxiliary(ii) auxiliary(iii) auxiliary(iv) ->
auxiliary for Relation of L;
end;
registration
let L be lower-bounded with_suprema transitive antisymmetric RelStr;
cluster auxiliary for Relation of L;
end;
theorem :: WAYBEL_4:1
for L being lower-bounded sup-Semilattice
for AR being auxiliary(ii) auxiliary(iii) Relation of L
for x, y, z, u being Element of L holds
[x, z] in AR & [y, u] in AR implies [x "\/" y, z "\/" u] in AR;
registration
let L be lower-bounded sup-Semilattice;
cluster auxiliary(i) auxiliary(ii) -> transitive for Relation of L;
end;
registration
let L be RelStr;
cluster IntRel L -> auxiliary(i);
end;
registration
let L be transitive RelStr;
cluster IntRel L -> auxiliary(ii);
end;
registration
let L be with_suprema antisymmetric RelStr;
cluster IntRel L -> auxiliary(iii);
end;
registration
let L be lower-bounded antisymmetric non empty RelStr;
cluster IntRel L -> auxiliary(iv);
end;
reserve a for set;
definition
let L be lower-bounded sup-Semilattice;
func Aux L -> set means
:: WAYBEL_4:def 8
a in it iff a is auxiliary Relation of L;
end;
registration
let L be lower-bounded sup-Semilattice;
cluster Aux L -> non empty;
end;
theorem :: WAYBEL_4:2
for L being lower-bounded sup-Semilattice
for AR being auxiliary(i) Relation of L holds AR c= IntRel L;
theorem :: WAYBEL_4:3
for L being lower-bounded sup-Semilattice holds
Top InclPoset Aux L = IntRel L;
registration
let L be lower-bounded sup-Semilattice;
cluster InclPoset Aux L -> upper-bounded;
end;
definition
let L be non empty RelStr;
func AuxBottom L -> Relation of L means
:: WAYBEL_4:def 9
for x,y be Element of L holds [x,y] in it iff x = Bottom L;
end;
registration
let L be lower-bounded sup-Semilattice;
cluster AuxBottom L -> auxiliary;
end;
theorem :: WAYBEL_4:4
for L being lower-bounded sup-Semilattice
for AR being auxiliary(iv) Relation of L holds AuxBottom L c= AR;
theorem :: WAYBEL_4:5
for L being lower-bounded sup-Semilattice holds
Bottom InclPoset Aux L = AuxBottom L;
registration
let L be lower-bounded sup-Semilattice;
cluster InclPoset Aux L -> lower-bounded;
end;
theorem :: WAYBEL_4:6
for L being lower-bounded sup-Semilattice
for a,b being auxiliary(i) Relation of L holds
a /\ b is auxiliary(i) Relation of L;
theorem :: WAYBEL_4:7
for L being lower-bounded sup-Semilattice
for a,b being auxiliary(ii) Relation of L holds
a /\ b is auxiliary(ii) Relation of L;
theorem :: WAYBEL_4:8
for L being lower-bounded sup-Semilattice
for a,b being auxiliary(iii) Relation of L holds
a /\ b is auxiliary(iii) Relation of L;
theorem :: WAYBEL_4:9
for L being lower-bounded sup-Semilattice
for a,b being auxiliary(iv) Relation of L holds
a /\ b is auxiliary(iv) Relation of L;
theorem :: WAYBEL_4:10
for L being lower-bounded sup-Semilattice
for a,b being auxiliary Relation of L holds
a /\ b is auxiliary Relation of L;
theorem :: WAYBEL_4:11
for L being lower-bounded sup-Semilattice
for X being non empty Subset of InclPoset Aux L holds
meet X is auxiliary Relation of L;
registration
let L be lower-bounded sup-Semilattice;
cluster InclPoset Aux L -> with_infima;
end;
registration
let L be lower-bounded sup-Semilattice;
cluster InclPoset Aux L -> complete;
end;
definition
let L be non empty RelStr, x be Element of L;
let AR be Relation of the carrier of L;
func AR-below x -> Subset of L equals
:: WAYBEL_4:def 10
{y where y is Element of L: [y,x] in AR};
func AR-above x -> Subset of L equals
:: WAYBEL_4:def 11
{y where y is Element of L: [x,y] in AR};
end;
theorem :: WAYBEL_4:12
for L being lower-bounded sup-Semilattice, x being Element of L
for AR being auxiliary(i) Relation of L holds AR-below x c= downarrow x;
registration
let L be lower-bounded sup-Semilattice, x be Element of L;
let AR be auxiliary(iv) Relation of L;
cluster AR-below x -> non empty;
end;
registration
let L be lower-bounded sup-Semilattice, x be Element of L;
let AR be auxiliary(ii) Relation of L;
cluster AR-below x -> lower;
end;
registration
let L be lower-bounded sup-Semilattice, x be Element of L;
let AR be auxiliary(iii) Relation of L;
cluster AR-below x -> directed;
end;
definition
let L be lower-bounded sup-Semilattice;
let AR be auxiliary(ii) auxiliary(iii) auxiliary(iv) Relation of L;
func AR-below -> Function of L, InclPoset Ids L means
:: WAYBEL_4:def 12
for x be Element of L holds it.x = AR-below x;
end;
theorem :: WAYBEL_4:13
for L being non empty RelStr, AR being Relation of L
for a being object, y being Element of L
holds a in AR-below y iff [a,y] in AR;
theorem :: WAYBEL_4:14
for L being sup-Semilattice, AR being Relation of L
for y being Element of L holds a in AR-above y iff [y,a] in AR;
theorem :: WAYBEL_4:15
for L being lower-bounded sup-Semilattice,
AR being auxiliary(i) Relation of L for x being Element of L holds
AR = the InternalRel of L implies AR-below x = downarrow x;
definition
let L be non empty Poset;
func MonSet L -> strict RelStr means
:: WAYBEL_4:def 13
( a in the carrier of it iff
ex s be Function of L, InclPoset Ids L st a = s & s is monotone &
for x be Element of L holds s.x c= downarrow x ) &
for c, d be object holds [c,d] in the InternalRel of it iff
ex f,g be Function of L, InclPoset Ids L st c = f & d = g &
c in the carrier of it & d in the carrier of it & f <= g;
end;
theorem :: WAYBEL_4:16
for L being lower-bounded sup-Semilattice holds
MonSet L is full SubRelStr of (InclPoset Ids L)|^(the carrier of L);
theorem :: WAYBEL_4:17
for L being lower-bounded sup-Semilattice,
AR being auxiliary(ii) Relation of L for x, y being Element of L holds
x <= y implies AR-below x c= AR-below y;
registration
let L be lower-bounded sup-Semilattice;
let AR be auxiliary(ii) auxiliary(iii) auxiliary(iv) Relation of L;
cluster AR-below -> monotone;
end;
theorem :: WAYBEL_4:18
for L being lower-bounded sup-Semilattice, AR being auxiliary Relation of L
holds AR-below in the carrier of MonSet L;
registration
let L be lower-bounded sup-Semilattice;
cluster MonSet L -> non empty;
end;
theorem :: WAYBEL_4:19
for L being lower-bounded sup-Semilattice holds
IdsMap L in the carrier of MonSet L;
theorem :: WAYBEL_4:20
for L being lower-bounded sup-Semilattice, AR being auxiliary Relation of L
holds AR-below <= IdsMap L;
theorem :: WAYBEL_4:21
for L being lower-bounded non empty Poset
for I being Ideal of L holds Bottom L in I;
theorem :: WAYBEL_4:22
for L being upper-bounded non empty Poset
for F being Filter of L holds Top L in F;
theorem :: WAYBEL_4:23
for L being lower-bounded non empty Poset holds
downarrow Bottom L = {Bottom L};
theorem :: WAYBEL_4:24
for L being upper-bounded non empty Poset holds uparrow Top L = {Top L};
reserve L for lower-bounded sup-Semilattice;
reserve x for Element of L;
theorem :: WAYBEL_4:25
(the carrier of L) --> {Bottom L} is Function of L, InclPoset Ids L;
theorem :: WAYBEL_4:26
(the carrier of L) --> {Bottom L} in the carrier of MonSet L;
theorem :: WAYBEL_4:27
for AR being auxiliary Relation of L holds
[(the carrier of L) --> {Bottom L} , AR-below] in the InternalRel of MonSet L
;
registration
let L;
cluster MonSet L -> upper-bounded;
end;
definition
let L;
func Rel2Map L -> Function of InclPoset Aux L, MonSet L means
:: WAYBEL_4:def 14
for AR being auxiliary Relation of L holds it.AR = AR-below;
end;
theorem :: WAYBEL_4:28
for R1, R2 being auxiliary Relation of L st R1 c= R2 holds
R1-below <= R2-below;
theorem :: WAYBEL_4:29
for R1, R2 being Relation of L st R1 c= R2 holds R1-below x c= R2-below x;
registration
let L;
cluster Rel2Map L -> monotone;
end;
definition
let L;
func Map2Rel L -> Function of MonSet L, InclPoset Aux L means
:: WAYBEL_4:def 15
for s be object st s in the carrier of MonSet L
ex AR be auxiliary Relation of L st AR = it.s & for x,y be object holds
[x,y] in AR iff ex x9,y9 be Element of L,
s9 be Function of L, InclPoset Ids L st
x9 = x & y9 = y & s9 = s & x9 in s9.y9;
end;
registration
let L;
cluster Map2Rel L -> monotone;
end;
theorem :: WAYBEL_4:30
(Map2Rel L) * (Rel2Map L) = id dom (Rel2Map L);
theorem :: WAYBEL_4:31
(Rel2Map L) * (Map2Rel L) = id (the carrier of MonSet L);
registration
let L;
cluster Rel2Map L -> one-to-one;
end;
:: Proposition 1.10 (i) p.43
theorem :: WAYBEL_4:32
(Rel2Map L)" = Map2Rel L;
:: Proposition 1.10 (ii) p.43
theorem :: WAYBEL_4:33
Rel2Map L is isomorphic;
theorem :: WAYBEL_4:34
for L being complete LATTICE, x being Element of L holds
meet { I where I is Ideal of L : x <= sup I } = waybelow x;
definition
let L be Semilattice, I be Ideal of L;
func DownMap I -> Function of L, InclPoset Ids L means
:: WAYBEL_4:def 16
for x be Element of L holds
( x <= sup I implies it.x = ( downarrow x ) /\ I ) &
( not x <= sup I implies it.x = downarrow x );
end;
theorem :: WAYBEL_4:35
for L being Semilattice, I being Ideal of L holds
DownMap I in the carrier of MonSet L;
theorem :: WAYBEL_4:36
for L being with_infima antisymmetric reflexive RelStr, x being Element of L
for D being non empty lower Subset of L holds
{x} "/\" D = (downarrow x) /\ D;
begin :: Approximating Relations
:: Definition 1.11 p.44
definition
let L be non empty RelStr, AR be Relation of L;
attr AR is approximating means
:: WAYBEL_4:def 17
for x be Element of L holds x = sup (AR-below x);
end;
definition
let L be non empty Poset;
let mp be Function of L, InclPoset Ids L;
attr mp is approximating means
:: WAYBEL_4:def 18
for x be Element of L ex ii be Subset of L st ii = mp.x & x = sup ii;
end;
:: Lemma 1.12 (i) p.44
theorem :: WAYBEL_4:37
for L being lower-bounded meet-continuous Semilattice, I being Ideal of L
holds DownMap I is approximating;
:: Lemma 1.12 (ii) p.44
theorem :: WAYBEL_4:38
for L being lower-bounded continuous LATTICE holds L is meet-continuous;
registration
cluster continuous -> meet-continuous for lower-bounded LATTICE;
end;
:: Lemma 1.12 (iii) p.44
theorem :: WAYBEL_4:39
for L being lower-bounded continuous LATTICE,
I being Ideal of L holds DownMap I is approximating;
registration
let L be non empty reflexive antisymmetric RelStr;
cluster L-waybelow -> auxiliary(i);
end;
registration
let L be non empty reflexive transitive RelStr;
cluster L-waybelow -> auxiliary(ii);
end;
registration
let L be with_suprema Poset;
cluster L-waybelow -> auxiliary(iii);
end;
registration
let L be /\-complete non empty Poset;
cluster L-waybelow -> auxiliary(iii);
end;
registration
let L be lower-bounded antisymmetric reflexive non empty RelStr;
cluster L-waybelow -> auxiliary(iv);
end;
theorem :: WAYBEL_4:40
for L being complete LATTICE, x being Element of L holds
(L-waybelow)-below x = waybelow x;
theorem :: WAYBEL_4:41
for L being LATTICE holds IntRel L is approximating;
registration
let L be lower-bounded continuous LATTICE;
cluster L-waybelow -> approximating;
end;
registration
let L be complete LATTICE;
cluster approximating auxiliary for Relation of L;
end;
definition
let L be complete LATTICE;
func App L -> set means
:: WAYBEL_4:def 19
a in it iff a is approximating auxiliary Relation of L;
end;
registration
let L be complete LATTICE;
cluster App L -> non empty;
end;
theorem :: WAYBEL_4:42
for L being complete LATTICE for mp being Function of L, InclPoset Ids L st
mp is approximating & mp in the carrier of MonSet L
ex AR being approximating auxiliary Relation of L st AR = (Map2Rel L).mp;
theorem :: WAYBEL_4:43
for L being complete LATTICE, x being Element of L holds
meet the set of all (DownMap I).x where I is Ideal of L = waybelow x;
:: Proposition 1.13 p.45
theorem :: WAYBEL_4:44
for L being lower-bounded meet-continuous LATTICE, x being Element of L holds
meet {AR-below x where AR is auxiliary Relation of L : AR in App L}
= waybelow x;
reserve L for complete LATTICE;
:: Proposition 1.14 p.45 ( 1 <=> 2 )
theorem :: WAYBEL_4:45
L is continuous iff for R being approximating auxiliary Relation of L holds
L-waybelow c= R & L-waybelow is approximating;
:: Proposition 1.14 p.45 ( 1 <=> 3 )
theorem :: WAYBEL_4:46
L is continuous iff (L is meet-continuous &
ex R being approximating auxiliary Relation of L st
for R9 being approximating auxiliary Relation of L holds R c= R9);
:: Definition 1.15 (SI) p.46
definition
let L be RelStr, AR be Relation of L;
attr AR is satisfying_SI means
:: WAYBEL_4:def 20
for x, z be Element of L holds ( [x,z] in AR & x <> z implies
ex y be Element of L st [x,y] in AR & [y,z] in AR & x <> y );
end;
:: Definition 1.15 (INT) p.46
definition
let L be RelStr, AR be Relation of L;
attr AR is satisfying_INT means
:: WAYBEL_4:def 21
for x, z be Element of L holds ( [x,z] in AR implies
ex y be Element of L st [x,y] in AR & [y,z] in AR );
end;
theorem :: WAYBEL_4:47
for L being RelStr, AR being Relation of L
holds AR is satisfying_SI implies AR is satisfying_INT;
registration
let L be non empty RelStr;
cluster satisfying_SI -> satisfying_INT for Relation of L;
end;
reserve AR for Relation of L;
reserve x, y, z for Element of L;
theorem :: WAYBEL_4:48
for AR being approximating Relation of L st
not x <= y holds ex u being Element of L st [u,x] in AR & not u <= y;
:: Lemma 1.16 p.46
theorem :: WAYBEL_4:49
for R being approximating auxiliary(i) auxiliary(iii) Relation of L holds
[x,z] in R & x <> z implies ex y st x <= y & [y,z] in R & x <> y;
:: Lemma 1.17 p.46
theorem :: WAYBEL_4:50
for R being approximating auxiliary Relation of L holds
x << z & x <> z implies
ex y being Element of L st [x,y] in R & [y,z] in R & x <> y;
:: Theorem 1.18 p.47
theorem :: WAYBEL_4:51
for L being lower-bounded continuous LATTICE
holds L-waybelow is satisfying_SI;
registration
let L be lower-bounded continuous LATTICE;
cluster L-waybelow -> satisfying_SI;
end;
theorem :: WAYBEL_4:52
for L being lower-bounded continuous LATTICE,
x,y being Element of L st x << y
ex x9 being Element of L st x << x9 & x9 << y;
:: Corollary 1.19 p.47
theorem :: WAYBEL_4:53
for L being lower-bounded continuous LATTICE holds
for x,y being Element of L holds ( x << y iff
for D being non empty directed Subset of L st y <= sup D
ex d being Element of L st d in D & x << d );
begin :: Exercises
definition
let L be RelStr, X be Subset of L, R be Relation of the carrier of L;
pred X is_directed_wrt R means
:: WAYBEL_4:def 22
for x,y being Element of L st x in X & y in X
ex z being Element of L st z in X & [x,z] in R & [y,z] in R;
end;
theorem :: WAYBEL_4:54
for L being RelStr, X being Subset of L st
X is_directed_wrt (the InternalRel of L) holds X is directed;
definition
let X be set, x be object;
let R be Relation;
pred x is_maximal_wrt X,R means
:: WAYBEL_4:def 23
x in X & not ex y being set st y in X & y <> x & [x,y] in R;
end;
definition
let L be RelStr, X be set, x be Element of L;
pred x is_maximal_in X means
:: WAYBEL_4:def 24
x is_maximal_wrt X, the InternalRel of L;
end;
theorem :: WAYBEL_4:55
for L being RelStr, X being set, x being Element of L holds
x is_maximal_in X iff x in X & not ex y being Element of L st y in X & x < y;
definition
let X be set, x be object;
let R be Relation;
pred x is_minimal_wrt X,R means
:: WAYBEL_4:def 25
x in X & not ex y being set st y in X & y <> x & [y,x] in R;
end;
definition
let L be RelStr, X be set, x be Element of L;
pred x is_minimal_in X means
:: WAYBEL_4:def 26
x is_minimal_wrt X, the InternalRel of L;
end;
theorem :: WAYBEL_4:56
for L being RelStr, X being set, x being Element of L holds
x is_minimal_in X iff x in X & not ex y being Element of L st y in X & x > y;
:: Exercise 1.23 (i) ( 1 => 2 )
theorem :: WAYBEL_4:57
AR is satisfying_SI implies
for x holds ( ex y st y is_maximal_wrt (AR-below x), AR )
implies [x,x] in AR;
:: Exercise 1.23 (i) ( 2 => 1 )
theorem :: WAYBEL_4:58
( for x holds ( ex y st y is_maximal_wrt (AR-below x), AR )
implies [x,x] in AR ) implies AR is satisfying_SI;
:: Exercise 1.23 (ii) ( 3 => 4 )
theorem :: WAYBEL_4:59
for AR being auxiliary(ii) auxiliary(iii) Relation of L holds
AR is satisfying_INT implies for x holds AR-below x is_directed_wrt AR;
:: Exercise 1.23 (ii) ( 4 => 3 )
theorem :: WAYBEL_4:60
( for x holds AR-below x is_directed_wrt AR) implies AR is satisfying_INT;
:: Exercise 1.23 (iii) p.51
theorem :: WAYBEL_4:61
for R being approximating auxiliary(i) auxiliary(ii) auxiliary(iii)
Relation of L st R is satisfying_INT holds R is satisfying_SI;
registration
let L;
cluster satisfying_INT ->
satisfying_SI for approximating auxiliary Relation of L;
end;