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
  for r1, r2, r3 being Complex holds Product <*r1,r2,r3*> = r1 * r2 * r3
proof
  let r1, r2, r3 be Complex;
  thus Product <*r1,r2,r3*> = Product <*r1,r2*> * r3 by Th96
    .= r1 * r2 * r3 by Th99;
end;
