reserve s for set,
  i,j for natural Number,
  k for Nat,
  x,x1,x2,x3 for Real,
  r,r1,r2,r3,r4 for Real,
  F,F1,F2,F3 for real-valued FinSequence,
  R,R1,R2 for Element of i-tuples_on REAL;

theorem Th99:
  for r1, r2 being Complex holds Product <*r1,r2*> = r1 * r2
proof
  let r1, r2 be Complex;
  thus Product <*r1,r2*> = Product <*r1*> * r2 by Th96
    .= r1 * r2;
end;
