theorem
  mlt(<*r1*>,<*r2*>) = <*r1*r2*>
proof
  reconsider s1=r1, s2=r2 as Element of REAL by XREAL_0:def 1;
  mlt(<*s1*>,<*s2*>) = <*multreal.(s1,s2)*> by FINSEQ_2:74
    .= <*r1*r2*> by BINOP_2:def 11;
  hence thesis;
end;
