let h be non constant standard special_circular_sequence; :: thesis: for I, i1, i being Nat
for Y being non empty finite Subset of NAT st 1 <= i & i <= len h & 1 <= I & I <= width (GoB h) & Y = { j where j is Element of NAT : ( [j,I] in Indices (GoB h) & ex k being Nat st
( k in dom h & h /. k = (GoB h) * (j,I) ) )
}
& (h /. i) `2 = ((GoB h) * (1,I)) `2 & i1 = min Y holds
((GoB h) * (i1,I)) `1 <= (h /. i) `1

let I, i1, i be Nat; :: thesis: for Y being non empty finite Subset of NAT st 1 <= i & i <= len h & 1 <= I & I <= width (GoB h) & Y = { j where j is Element of NAT : ( [j,I] in Indices (GoB h) & ex k being Nat st
( k in dom h & h /. k = (GoB h) * (j,I) ) )
}
& (h /. i) `2 = ((GoB h) * (1,I)) `2 & i1 = min Y holds
((GoB h) * (i1,I)) `1 <= (h /. i) `1

let Y be non empty finite Subset of NAT; :: thesis: ( 1 <= i & i <= len h & 1 <= I & I <= width (GoB h) & Y = { j where j is Element of NAT : ( [j,I] in Indices (GoB h) & ex k being Nat st
( k in dom h & h /. k = (GoB h) * (j,I) ) )
}
& (h /. i) `2 = ((GoB h) * (1,I)) `2 & i1 = min Y implies ((GoB h) * (i1,I)) `1 <= (h /. i) `1 )

A1: h /. i = |[((h /. i) `1),((h /. i) `2)]| by EUCLID:53;
assume A2: ( 1 <= i & i <= len h & 1 <= I & I <= width (GoB h) & Y = { j where j is Element of NAT : ( [j,I] in Indices (GoB h) & ex k being Nat st
( k in dom h & h /. k = (GoB h) * (j,I) ) )
}
& (h /. i) `2 = ((GoB h) * (1,I)) `2 & i1 = min Y ) ; :: thesis: ((GoB h) * (i1,I)) `1 <= (h /. i) `1
then A3: i in dom h by FINSEQ_3:25;
then consider i2, j2 being Nat such that
A4: [i2,j2] in Indices (GoB h) and
A5: h /. i = (GoB h) * (i2,j2) by GOBOARD5:11;
A6: i2 <= len (GoB h) by ;
A7: 1 <= i2 by ;
then A8: [i2,I] in Indices (GoB h) by ;
A9: j2 <= width (GoB h) by ;
1 <= j2 by ;
then A10: (h /. i) `1 = ((GoB h) * (i2,1)) `1 by
.= ((GoB h) * (i2,I)) `1 by ;
i1 in Y by ;
then ex j being Element of NAT st
( i1 = j & [j,I] in Indices (GoB h) & ex k being Nat st
( k in dom h & h /. k = (GoB h) * (j,I) ) ) by A2;
then A11: 1 <= i1 by MATRIX_0:32;
A12: i2 in NAT by ORDINAL1:def 12;
(h /. i) `2 = ((GoB h) * (i2,I)) `2 by ;
then h /. i = (GoB h) * (i2,I) by ;
then i2 in Y by A2, A3, A8, A12;
then A13: i1 <= i2 by ;
A14: i2 <= len (GoB h) by ;
now :: thesis: ( ( i1 < i2 & ((GoB h) * (i1,I)) `1 <= ((GoB h) * (i2,I)) `1 ) or ( i1 >= i2 & ((GoB h) * (i1,I)) `1 <= ((GoB h) * (i2,I)) `1 ) )
per cases ( i1 < i2 or i1 >= i2 ) ;
case i1 < i2 ; :: thesis: ((GoB h) * (i1,I)) `1 <= ((GoB h) * (i2,I)) `1
hence ((GoB h) * (i1,I)) `1 <= ((GoB h) * (i2,I)) `1 by ; :: thesis: verum
end;
case i1 >= i2 ; :: thesis: ((GoB h) * (i1,I)) `1 <= ((GoB h) * (i2,I)) `1
hence ((GoB h) * (i1,I)) `1 <= ((GoB h) * (i2,I)) `1 by ; :: thesis: verum
end;
end;
end;
hence ((GoB h) * (i1,I)) `1 <= (h /. i) `1 by A10; :: thesis: verum