let E be set ; :: thesis: for A being Subset of (E ^omega) holds
( <%> E in A + iff <%> E in A )
let A be Subset of (E ^omega); :: thesis: ( <%> E in A + iff <%> E in A )
A + = A |^.. 1 by Th50;
hence ( <%> E in A + iff <%> E in A ) by Th10; :: thesis: verum