let E be set ; :: thesis: for A being Subset of (E ^omega)
for n being Nat st n <= 1 holds
A |^ n c= A ?
let A be Subset of (E ^omega); :: thesis: for n being Nat st n <= 1 holds
A |^ n c= A ?
let n be Nat; :: thesis: ( n <= 1 implies A |^ n c= A ? )
assume n <= 1 ; :: thesis: A |^ n c= A ?
then for x being set st x in A |^ n holds
x in A ? by Th73;
hence A |^ n c= A ? by TARSKI:def 3; :: thesis: verum