let Y be non empty set ; :: thesis: for a being Element of Funcs Y,BOOLEAN
for G being Subset of (PARTITIONS Y)
for P, Q being a_partition of Y st G is independent holds
All (All a,P,G),Q,G = All (All a,Q,G),P,G

let a be Element of Funcs Y,BOOLEAN ; :: thesis: for G being Subset of (PARTITIONS Y)
for P, Q being a_partition of Y st G is independent holds
All (All a,P,G),Q,G = All (All a,Q,G),P,G

let G be Subset of (PARTITIONS Y); :: thesis: for P, Q being a_partition of Y st G is independent holds
All (All a,P,G),Q,G = All (All a,Q,G),P,G

let P, Q be a_partition of Y; :: thesis: ( G is independent implies All (All a,P,G),Q,G = All (All a,Q,G),P,G )
set A = G \ {P};
set B = G \ {Q};
A1: CompF P,G = '/\' (G \ {P}) by BVFUNC_2:def 7;
A2: ( G \ {P} c= G & G \ {Q} c= G ) by XBOOLE_1:36;
A3: CompF Q,G = '/\' (G \ {Q}) by BVFUNC_2:def 7;
assume G is independent ; :: thesis: All (All a,P,G),Q,G = All (All a,Q,G),P,G
then A4: (ERl ('/\' (G \ {P}))) * (ERl ('/\' (G \ {Q}))) = (ERl ('/\' (G \ {Q}))) * (ERl ('/\' (G \ {P}))) by A2, Th16;
A5: for y being Element of Y holds
( ( ( for x being Element of Y st x in EqClass y,(CompF Q,G) holds
(B_INF a,(CompF P,G)) . x = TRUE ) implies (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = TRUE ) & ( ex x being Element of Y st
( x in EqClass y,(CompF Q,G) & not (B_INF a,(CompF P,G)) . x = TRUE ) implies (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = FALSE ) )
proof
let y be Element of Y; :: thesis: ( ( ( for x being Element of Y st x in EqClass y,(CompF Q,G) holds
(B_INF a,(CompF P,G)) . x = TRUE ) implies (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = TRUE ) & ( ex x being Element of Y st
( x in EqClass y,(CompF Q,G) & not (B_INF a,(CompF P,G)) . x = TRUE ) implies (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = FALSE ) )

hereby :: thesis: ( ex x being Element of Y st
( x in EqClass y,(CompF Q,G) & not (B_INF a,(CompF P,G)) . x = TRUE ) implies (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = FALSE )
assume A6: for x being Element of Y st x in EqClass y,(CompF Q,G) holds
(B_INF a,(CompF P,G)) . x = TRUE ; :: thesis: (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = TRUE
for x being Element of Y st x in EqClass y,(CompF P,G) holds
(B_INF a,(CompF Q,G)) . x = TRUE
proof
let x be Element of Y; :: thesis: ( x in EqClass y,(CompF P,G) implies (B_INF a,(CompF Q,G)) . x = TRUE )
assume x in EqClass y,(CompF P,G) ; :: thesis: (B_INF a,(CompF Q,G)) . x = TRUE
then A7: [x,y] in ERl ('/\' (G \ {P})) by A1, Th5;
for z being Element of Y st z in EqClass x,(CompF Q,G) holds
a . z = TRUE
proof
let z be Element of Y; :: thesis: ( z in EqClass x,(CompF Q,G) implies a . z = TRUE )
assume z in EqClass x,(CompF Q,G) ; :: thesis: a . z = TRUE
then [z,x] in ERl ('/\' (G \ {Q})) by A3, Th5;
then [z,y] in (ERl ('/\' (G \ {P}))) * (ERl ('/\' (G \ {Q}))) by A4, A7, RELAT_1:def 8;
then consider u being set such that
A8: [z,u] in ERl ('/\' (G \ {P})) and
A9: [u,y] in ERl ('/\' (G \ {Q})) by RELAT_1:def 8;
u in field (ERl ('/\' (G \ {Q}))) by A9, RELAT_1:30;
then reconsider u = u as Element of Y by ORDERS_1:97;
u in EqClass y,(CompF Q,G) by A3, A9, Th5;
then A10: (B_INF a,(CompF P,G)) . u <> FALSE by A6;
z in EqClass u,(CompF P,G) by A1, A8, Th5;
hence a . z = TRUE by A10, BVFUNC_1:def 19; :: thesis: verum
end;
hence (B_INF a,(CompF Q,G)) . x = TRUE by BVFUNC_1:def 19; :: thesis: verum
end;
hence (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = TRUE by BVFUNC_1:def 19; :: thesis: verum
end;
given x being Element of Y such that A11: x in EqClass y,(CompF Q,G) and
A12: (B_INF a,(CompF P,G)) . x <> TRUE ; :: thesis: (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = FALSE
consider z being Element of Y such that
A13: z in EqClass x,(CompF P,G) and
A14: a . z <> TRUE by A12, BVFUNC_1:def 19;
A15: [x,y] in ERl ('/\' (G \ {Q})) by A3, A11, Th5;
[z,x] in ERl ('/\' (G \ {P})) by A1, A13, Th5;
then [z,y] in (ERl ('/\' (G \ {Q}))) * (ERl ('/\' (G \ {P}))) by A4, A15, RELAT_1:def 8;
then consider u being set such that
A16: [z,u] in ERl ('/\' (G \ {Q})) and
A17: [u,y] in ERl ('/\' (G \ {P})) by RELAT_1:def 8;
u in field (ERl ('/\' (G \ {Q}))) by A16, RELAT_1:30;
then reconsider u = u as Element of Y by ORDERS_1:97;
z in EqClass u,(CompF Q,G) by A3, A16, Th5;
then A18: (B_INF a,(CompF Q,G)) . u = FALSE by A14, BVFUNC_1:def 19;
u in EqClass y,(CompF P,G) by A1, A17, Th5;
hence (B_INF (B_INF a,(CompF Q,G)),(CompF P,G)) . y = FALSE by A18, BVFUNC_1:def 19; :: thesis: verum
end;
thus All (All a,P,G),Q,G = B_INF (All a,P,G),(CompF Q,G) by BVFUNC_2:def 9
.= B_INF (B_INF a,(CompF P,G)),(CompF Q,G) by BVFUNC_2:def 9
.= B_INF (B_INF a,(CompF Q,G)),(CompF P,G) by A5, BVFUNC_1:def 19
.= B_INF (All a,Q,G),(CompF P,G) by BVFUNC_2:def 9
.= All (All a,Q,G),P,G by BVFUNC_2:def 9 ; :: thesis: verum