let E be set ; :: thesis: for A being Subset of (E ^omega )
for k being Nat holds (A ? ) |^ k c= A *
let A be Subset of (E ^omega ); :: thesis: for k being Nat holds (A ? ) |^ k c= A *
let k be Nat; :: thesis: (A ? ) |^ k c= A *
(A ? ) |^ k = (A |^ 0 ,1) |^ k by Th79;
hence (A ? ) |^ k c= A * by Th32, FLANG_1:60; :: thesis: verum