reserve i,j,k,n,m for Nat,
  x,y,z,y1,y2 for object, X,Y,D for set,
  p,q for XFinSequence;
reserve k1,k2 for Nat;
reserve D for non empty set,
  F,G for XFinSequence of D,
  b for BinOp of D,
  d,d1,d2 for Element of D;
reserve F for XFinSequence,
        rF,rF1,rF2 for real-valued XFinSequence,
        r for Real,
        cF,cF1,cF2 for complex-valued XFinSequence,
        c,c1,c2 for Complex;

theorem
  for D being set, p,q be Element of D^omega holds FlattenSeq <% p,q %> = p ^ q
proof
  let D be set, p,q be Element of D^omega;
  consider g being BinOp of D^omega such that
A1: for d1,d2 being Element of D^omega holds g.(d1,d2) = d1^d2 and
A2: FlattenSeq <% p,q %> = g "**" <% p,q %> by Def10;
  thus FlattenSeq <% p,q %> = g.(p,q) by A2,Th38
    .= p ^ q by A1;
end;
