let Y be non empty set ; :: thesis: for G being Subset of (PARTITIONS Y)
for u, a being Element of Funcs Y,BOOLEAN
for PA being a_partition of Y st u is_independent_of PA,G holds
Ex (u '&' a),PA,G = u '&' (Ex a,PA,G)

let G be Subset of (PARTITIONS Y); :: thesis: for u, a being Element of Funcs Y,BOOLEAN
for PA being a_partition of Y st u is_independent_of PA,G holds
Ex (u '&' a),PA,G = u '&' (Ex a,PA,G)

let u, a be Element of Funcs Y,BOOLEAN ; :: thesis: for PA being a_partition of Y st u is_independent_of PA,G holds
Ex (u '&' a),PA,G = u '&' (Ex a,PA,G)

let PA be a_partition of Y; :: thesis: ( u is_independent_of PA,G implies Ex (u '&' a),PA,G = u '&' (Ex a,PA,G) )
assume u is_independent_of PA,G ; :: thesis: Ex (u '&' a),PA,G = u '&' (Ex a,PA,G)
then A1: u is_dependent_of CompF PA,G by Def8;
A2: Ex (u '&' a),PA,G '<' u '&' (Ex a,PA,G)
proof
let z be Element of Y; :: according to BVFUNC_1:def 15 :: thesis: ( not (Ex (u '&' a),PA,G) . z = TRUE or (u '&' (Ex a,PA,G)) . z = TRUE )
assume (Ex (u '&' a),PA,G) . z = TRUE ; :: thesis: (u '&' (Ex a,PA,G)) . z = TRUE
then consider x1 being Element of Y such that
A3: x1 in EqClass z,(CompF PA,G) and
A4: (u '&' a) . x1 = TRUE by BVFUNC_1:def 20;
A5: (u . x1) '&' (a . x1) = TRUE by A4, MARGREL1:def 21;
then a . x1 = TRUE by MARGREL1:45;
then A6: (Ex a,PA,G) . z = TRUE by A3, BVFUNC_1:def 20;
z in EqClass z,(CompF PA,G) by EQREL_1:def 8;
then A7: u . z = u . x1 by A1, A3, BVFUNC_1:def 18;
u . x1 = TRUE by A5, MARGREL1:45;
then (u '&' (Ex a,PA,G)) . z = TRUE '&' TRUE by A6, A7, MARGREL1:def 21
.= TRUE ;
hence (u '&' (Ex a,PA,G)) . z = TRUE ; :: thesis: verum
end;
u '&' (Ex a,PA,G) '<' Ex (u '&' a),PA,G
proof
let z be Element of Y; :: according to BVFUNC_1:def 15 :: thesis: ( not (u '&' (Ex a,PA,G)) . z = TRUE or (Ex (u '&' a),PA,G) . z = TRUE )
assume (u '&' (Ex a,PA,G)) . z = TRUE ; :: thesis: (Ex (u '&' a),PA,G) . z = TRUE
then A8: (u . z) '&' ((Ex a,PA,G) . z) = TRUE by MARGREL1:def 21;
then A9: u . z = TRUE by MARGREL1:45;
(Ex a,PA,G) . z = TRUE by A8, MARGREL1:45;
then consider x1 being Element of Y such that
A10: x1 in EqClass z,(CompF PA,G) and
A11: a . x1 = TRUE by BVFUNC_1:def 20;
z in EqClass z,(CompF PA,G) by EQREL_1:def 8;
then u . x1 = u . z by A1, A10, BVFUNC_1:def 18;
then (u '&' a) . x1 = TRUE '&' TRUE by A9, A11, MARGREL1:def 21
.= TRUE ;
hence (Ex (u '&' a),PA,G) . z = TRUE by A10, BVFUNC_1:def 20; :: thesis: verum
end;
hence Ex (u '&' a),PA,G = u '&' (Ex a,PA,G) by A2, BVFUNC_1:18; :: thesis: verum