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
All (u 'xor' a),PA,G '<' u 'xor' (All 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
All (u 'xor' a),PA,G '<' u 'xor' (All 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
All (u 'xor' a),PA,G '<' u 'xor' (All a,PA,G)

let PA be a_partition of Y; :: thesis: ( u is_independent_of PA,G implies All (u 'xor' a),PA,G '<' u 'xor' (All a,PA,G) )
A1: ( 'not' FALSE = TRUE & 'not' TRUE = FALSE ) by MARGREL1:41;
assume u is_independent_of PA,G ; :: thesis: All (u 'xor' a),PA,G '<' u 'xor' (All a,PA,G)
then A2: u is_dependent_of CompF PA,G by Def8;
let z be Element of Y; :: according to BVFUNC_1:def 15 :: thesis: ( not (All (u 'xor' a),PA,G) . z = TRUE or (u 'xor' (All a,PA,G)) . z = TRUE )
assume A3: (All (u 'xor' a),PA,G) . z = TRUE ; :: thesis: (u 'xor' (All a,PA,G)) . z = TRUE
A4: ( z in EqClass z,(CompF PA,G) & EqClass z,(CompF PA,G) in CompF PA,G ) by EQREL_1:def 8;
A5: (u 'xor' (All a,PA,G)) . z = ((All a,PA,G) . z) 'xor' (u . z) by BVFUNC_1:def 8;
per cases ( ( ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
u . x = TRUE ) & ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
a . x = TRUE ) ) or ( ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
u . x = TRUE ) & ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not a . x = TRUE ) ) or ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not u . x = TRUE ) )
;
suppose A6: ( ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
u . x = TRUE ) & ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
a . x = TRUE ) ) ; :: thesis: (u 'xor' (All a,PA,G)) . z = TRUE
end;
suppose A10: ( ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
u . x = TRUE ) & ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not a . x = TRUE ) ) ; :: thesis: (u 'xor' (All a,PA,G)) . z = TRUE
then A11: (All a,PA,G) . z = FALSE by BVFUNC_1:def 19;
consider x1 being Element of Y such that
A12: ( x1 in EqClass z,(CompF PA,G) & a . x1 <> TRUE ) by A10;
A13: u . x1 = TRUE by A10, A12;
u . z = u . x1 by A2, A4, A12, BVFUNC_1:def 18;
then (u 'xor' (All a,PA,G)) . z = TRUE 'or' FALSE by A1, A5, A11, A13
.= TRUE by BINARITH:7 ;
hence (u 'xor' (All a,PA,G)) . z = TRUE ; :: thesis: verum
end;
suppose ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not u . x = TRUE ) ; :: thesis: (u 'xor' (All a,PA,G)) . z = TRUE
then consider x1 being Element of Y such that
A14: ( x1 in EqClass z,(CompF PA,G) & u . x1 <> TRUE ) ;
now
per cases ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
a . x = TRUE or ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not a . x = TRUE ) )
;
suppose for x being Element of Y st x in EqClass z,(CompF PA,G) holds
a . x = TRUE ; :: thesis: (u 'xor' (All a,PA,G)) . z = TRUE
then A15: (All a,PA,G) . z = TRUE by BVFUNC_1:def 19;
u . z = u . x1 by A2, A4, A14, BVFUNC_1:def 18;
then u . z = FALSE by A14, XBOOLEAN:def 3;
then (u 'xor' (All a,PA,G)) . z = FALSE 'or' TRUE by A1, A5, A15
.= TRUE by BINARITH:7 ;
hence (u 'xor' (All a,PA,G)) . z = TRUE ; :: thesis: verum
end;
suppose ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not a . x = TRUE ) ; :: thesis: (u 'xor' (All a,PA,G)) . z = TRUE
then consider x2 being Element of Y such that
A16: ( x2 in EqClass z,(CompF PA,G) & a . x2 <> TRUE ) ;
u . x1 = u . x2 by A2, A14, A16, BVFUNC_1:def 18;
then A17: u . x2 = FALSE by A14, XBOOLEAN:def 3;
A18: a . x2 = FALSE by A16, XBOOLEAN:def 3;
(u 'xor' a) . x2 = (a . x2) 'xor' (u . x2) by BVFUNC_1:def 8
.= FALSE by A17, A18, MARGREL1:45 ;
hence (u 'xor' (All a,PA,G)) . z = TRUE by A3, A16, BVFUNC_1:def 19; :: thesis: verum
end;
end;
end;
hence (u 'xor' (All a,PA,G)) . z = TRUE ; :: thesis: verum
end;
end;