let E be set ; :: thesis: for A being Subset of holds A |^ 0 = {(<%> E)}
let A be Subset of ; :: thesis: A |^ 0 = {(<%> E)}
ex concat being Function of NAT , bool (E ^omega ) st
( A |^ 0 = concat . 0 & concat . 0 = {(<%> E)} & ( for i being Nat holds concat . (i + 1) = (concat . i) ^^ A ) ) by Def2;
hence A |^ 0 = {(<%> E)} ; :: thesis: verum