let E be set ; :: thesis: for A being Subset of (E ^omega) holds A ^^ (A +) = (A +) ^^ A
let A be Subset of (E ^omega); :: thesis: A ^^ (A +) = (A +) ^^ A
thus A ^^ (A +) = A ^^ (A |^.. 1) by Th50
.= (A |^.. 1) ^^ A by Th23
.= (A +) ^^ A by Th50 ; :: thesis: verum