let X be non empty TopSpace; for X0 being non empty maximal_Kolmogorov_subspace of X
for A being Subset of X holds (Stone-retraction X,X0) .: A = (Stone-retraction X,X0) .: (MaxADSet A)
let X0 be non empty maximal_Kolmogorov_subspace of X; for A being Subset of X holds (Stone-retraction X,X0) .: A = (Stone-retraction X,X0) .: (MaxADSet A)
let A be Subset of X; (Stone-retraction X,X0) .: A = (Stone-retraction X,X0) .: (MaxADSet A)
set r = Stone-retraction X,X0;
A1:
rng (Stone-retraction X,X0) = (Stone-retraction X,X0) .: the carrier of X
by FUNCT_2:45;
(Stone-retraction X,X0) .: ((Stone-retraction X,X0) " ((Stone-retraction X,X0) .: A)) = (Stone-retraction X,X0) .: (MaxADSet A)
by Th29;
hence
(Stone-retraction X,X0) .: A = (Stone-retraction X,X0) .: (MaxADSet A)
by A1, FUNCT_1:147, RELAT_1:156; verum