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

let PA be a_partition of Y; :: thesis: ( u is_independent_of PA,G implies All (u 'eqv' a),PA,G '<' u 'eqv' (All a,PA,G) )
A1: 'not' FALSE = TRUE by MARGREL1:41;
assume u is_independent_of PA,G ; :: thesis: All (u 'eqv' a),PA,G '<' u 'eqv' (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 'eqv' a),PA,G) . z = TRUE or (u 'eqv' (All a,PA,G)) . z = TRUE )
assume A3: (All (u 'eqv' a),PA,G) . z = TRUE ; :: thesis: (u 'eqv' (All a,PA,G)) . z = TRUE
A4: z in EqClass z,(CompF PA,G) by EQREL_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 ) & ( 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 u . x = TRUE ) & 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
u . x = TRUE ) & ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
a . x = TRUE ) ) ; :: thesis: (u 'eqv' (All a,PA,G)) . z = TRUE
then A5: ( (All a,PA,G) . z = TRUE & u . z = TRUE ) by A4, BVFUNC_1:def 19;
(u 'eqv' (All a,PA,G)) . z = 'not' ((u . z) 'xor' ((All a,PA,G) . z)) by BVFUNC_1:def 12
.= TRUE by A1, A5, MARGREL1:49 ;
hence (u 'eqv' (All a,PA,G)) . z = TRUE ; :: thesis: verum
end;
suppose A6: ( ( 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 'eqv' (All a,PA,G)) . z = TRUE
then consider x1 being Element of Y such that
A7: x1 in EqClass z,(CompF PA,G) and
A8: a . x1 <> TRUE ;
A9: u . x1 = TRUE by A6, A7;
A10: a . x1 = FALSE by A8, XBOOLEAN:def 3;
(u 'eqv' a) . x1 = 'not' ((u . x1) 'xor' (a . x1)) by BVFUNC_1:def 12
.= 'not' (FALSE 'or' TRUE ) by A1, A9, A10
.= 'not' TRUE by BINARITH:7
.= FALSE by MARGREL1:41 ;
hence (u 'eqv' (All a,PA,G)) . z = TRUE by A3, A7, BVFUNC_1:def 19; :: thesis: verum
end;
suppose A11: ( ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not u . x = TRUE ) & ( for x being Element of Y st x in EqClass z,(CompF PA,G) holds
a . x = TRUE ) ) ; :: thesis: (u 'eqv' (All a,PA,G)) . z = TRUE
then consider x1 being Element of Y such that
A12: x1 in EqClass z,(CompF PA,G) and
A13: u . x1 <> TRUE ;
A14: a . x1 = TRUE by A11, A12;
A15: u . x1 = FALSE by A13, XBOOLEAN:def 3;
(u 'eqv' a) . x1 = 'not' ((u . x1) 'xor' (a . x1)) by BVFUNC_1:def 12
.= 'not' (TRUE 'or' FALSE ) by A1, A15, A14
.= 'not' TRUE by BINARITH:7
.= FALSE by MARGREL1:41 ;
hence (u 'eqv' (All a,PA,G)) . z = TRUE by A3, A12, BVFUNC_1:def 19; :: thesis: verum
end;
suppose A16: ( ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not u . x = TRUE ) & ex x being Element of Y st
( x in EqClass z,(CompF PA,G) & not a . x = TRUE ) ) ; :: thesis: (u 'eqv' (All a,PA,G)) . z = TRUE
then consider x1 being Element of Y such that
A17: x1 in EqClass z,(CompF PA,G) and
A18: u . x1 <> TRUE ;
u . x1 = u . z by A2, A4, A17, BVFUNC_1:def 18;
then A19: u . z = FALSE by A18, XBOOLEAN:def 3;
A20: (All a,PA,G) . z = FALSE by A16, BVFUNC_1:def 19;
(u 'eqv' (All a,PA,G)) . z = 'not' ((u . z) 'xor' ((All a,PA,G) . z)) by BVFUNC_1:def 12
.= TRUE by A1, A20, A19, MARGREL1:49 ;
hence (u 'eqv' (All a,PA,G)) . z = TRUE ; :: thesis: verum
end;
end;