let E be set ; for A being Subset of (E ^omega )
for m, n being Nat holds (A ? ) ^^ (A |^ m,n) = (A |^ m,n) ^^ (A ? )
let A be Subset of (E ^omega ); for m, n being Nat holds (A ? ) ^^ (A |^ m,n) = (A |^ m,n) ^^ (A ? )
let m, n be Nat; (A ? ) ^^ (A |^ m,n) = (A |^ m,n) ^^ (A ? )
(A |^ 0 ,1) ^^ (A |^ m,n) = (A |^ m,n) ^^ (A |^ 0 ,1)
by Th39;
then
(A ? ) ^^ (A |^ m,n) = (A |^ m,n) ^^ (A |^ 0 ,1)
by Th79;
hence
(A ? ) ^^ (A |^ m,n) = (A |^ m,n) ^^ (A ? )
by Th79; verum