let C, D be non empty set ; :: thesis: for B being Element of Fin C
for e, d being Element of D
for F, G being BinOp of D
for f being Function of C,D st F is commutative & F is associative & F is having_a_unity & e = the_unity_wrt F & G is_distributive_wrt F & G . e,d = e holds
G . (F $$ B,f),d = F $$ B,(G [:] f,d)

let B be Element of Fin C; :: thesis: for e, d being Element of D
for F, G being BinOp of D
for f being Function of C,D st F is commutative & F is associative & F is having_a_unity & e = the_unity_wrt F & G is_distributive_wrt F & G . e,d = e holds
G . (F $$ B,f),d = F $$ B,(G [:] f,d)

let e, d be Element of D; :: thesis: for F, G being BinOp of D
for f being Function of C,D st F is commutative & F is associative & F is having_a_unity & e = the_unity_wrt F & G is_distributive_wrt F & G . e,d = e holds
G . (F $$ B,f),d = F $$ B,(G [:] f,d)

let F, G be BinOp of D; :: thesis: for f being Function of C,D st F is commutative & F is associative & F is having_a_unity & e = the_unity_wrt F & G is_distributive_wrt F & G . e,d = e holds
G . (F $$ B,f),d = F $$ B,(G [:] f,d)

let f be Function of C,D; :: thesis: ( F is commutative & F is associative & F is having_a_unity & e = the_unity_wrt F & G is_distributive_wrt F & G . e,d = e implies G . (F $$ B,f),d = F $$ B,(G [:] f,d) )
assume that
A1: ( F is commutative & F is associative ) and
A2: F is having_a_unity and
A3: e = the_unity_wrt F and
A4: G is_distributive_wrt F ; :: thesis: ( not G . e,d = e or G . (F $$ B,f),d = F $$ B,(G [:] f,d) )
defpred S1[ Element of Fin C] means G . (F $$ $1,f),d = F $$ $1,(G [:] f,d);
assume G . e,d = e ; :: thesis: G . (F $$ B,f),d = F $$ B,(G [:] f,d)
then G . (F $$ ({}. C),f),d = e by A1, A2, A3, SETWISEO:40
.= F $$ ({}. C),(G [:] f,d) by A1, A2, A3, SETWISEO:40 ;
then A5: S1[ {}. C] ;
A6: for B' being Element of Fin C
for b being Element of C st S1[B'] & not b in B' holds
S1[B' \/ {.b.}]
proof
let B' be Element of Fin C; :: thesis: for b being Element of C st S1[B'] & not b in B' holds
S1[B' \/ {.b.}]

let c be Element of C; :: thesis: ( S1[B'] & not c in B' implies S1[B' \/ {.c.}] )
assume that
A7: G . (F $$ B',f),d = F $$ B',(G [:] f,d) and
A8: not c in B' ; :: thesis: S1[B' \/ {.c.}]
thus G . (F $$ (B' \/ {.c.}),f),d = G . (F . (F $$ B',f),(f . c)),d by A1, A2, A8, Th4
.= F . (G . (F $$ B',f),d),(G . (f . c),d) by A4, BINOP_1:23
.= F . (F $$ B',(G [:] f,d)),((G [:] f,d) . c) by A7, FUNCOP_1:60
.= F $$ (B' \/ {.c.}),(G [:] f,d) by A1, A2, A8, Th4 ; :: thesis: verum
end;
for B being Element of Fin C holds S1[B] from SETWISEO:sch 2(A5, A6);
hence G . (F $$ B,f),d = F $$ B,(G [:] f,d) ; :: thesis: verum