reserve k,n for Nat,
  x,y,z,y1,y2 for object,X,Y for set,
  f,g for Function;
reserve p,q,r,s,t for XFinSequence;
reserve D for set;
reserve i for Nat;
reserve m for Nat,
        D for non empty set;
reserve l for Nat;
reserve M for Nat;

theorem
  p +* (p ^ q) = p ^ q & (p ^ q) +* p = p ^ q by Th71,FUNCT_4:97,98;
