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 . d,e = e holds
G . d,(F $$ B,f) = F $$ B,(G [;] d,f)

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 . d,e = e holds
G . d,(F $$ B,f) = F $$ B,(G [;] d,f)

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 . d,e = e holds
G . d,(F $$ B,f) = F $$ B,(G [;] d,f)

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 . d,e = e holds
G . d,(F $$ B,f) = F $$ B,(G [;] d,f)

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 . d,e = e implies G . d,(F $$ B,f) = F $$ B,(G [;] d,f) )
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 . d,e = e or G . d,(F $$ B,f) = F $$ B,(G [;] d,f) )
defpred S1[ Element of Fin C] means G . d,(F $$ $1,f) = F $$ $1,(G [;] d,f);
assume G . d,e = e ; :: thesis: G . d,(F $$ B,f) = F $$ B,(G [;] d,f)
then G . d,(F $$ ({}. C),f) = e by A1, A2, A3, SETWISEO:40
.= F $$ ({}. C),(G [;] d,f) 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 . d,(F $$ B',f) = F $$ B',(G [;] d,f) and
A8: not c in B' ; :: thesis: S1[B' \/ {.c.}]
thus G . d,(F $$ (B' \/ {.c.}),f) = G . d,(F . (F $$ B',f),(f . c)) by A1, A2, A8, Th4
.= F . (G . d,(F $$ B',f)),(G . d,(f . c)) by A4, BINOP_1:23
.= F . (F $$ B',(G [;] d,f)),((G [;] d,f) . c) by A7, FUNCOP_1:66
.= F $$ (B' \/ {.c.}),(G [;] d,f) by A1, A2, A8, Th4 ; :: thesis: verum
end;
for B being Element of Fin C holds S1[B] from SETWISEO:sch 2(A5, A6);
hence G . d,(F $$ B,f) = F $$ B,(G [;] d,f) ; :: thesis: verum