let X be non empty finite set ; for B being Subset-Family of X holds B c= saturated-subsets (X deps_encl_by B)
let B be Subset-Family of X; B c= saturated-subsets (X deps_encl_by B)
set F = X deps_encl_by B;
reconsider F9 = X deps_encl_by B as Full-family of X by Th33;
set M = Maximal_wrt F9;
let x be object ; TARSKI:def 3 ( not x in B or x in saturated-subsets (X deps_encl_by B) )
assume A1:
x in B
; x in saturated-subsets (X deps_encl_by B)
then reconsider x9 = x as Element of B ;
reconsider x99 = x as Subset of X by A1;
Maximal_wrt F9 is (M1)
by Th28;
then consider a9, b9 being Subset of X such that
A2:
[a9,b9] >= [x99,x99]
and
A3:
[a9,b9] in Maximal_wrt F9
;
A4:
a9 c= x99
by A2;
[a9,b9] in X deps_encl_by B
by A3;
then consider a, b being Subset of X such that
A5:
[a9,b9] = [a,b]
and
A6:
for c being set st c in B & a c= c holds
b c= c
;
A7:
a ^|^ b,X deps_encl_by B
by A3, A5;
a9 = a
by A5, XTUPLE_0:1;
then A8:
b c= x9
by A1, A4, A6;
A9:
b9 = b
by A5, XTUPLE_0:1;
x99 c= b9
by A2;
then
b = x
by A9, A8, XBOOLE_0:def 10;
hence
x in saturated-subsets (X deps_encl_by B)
by A7; verum