const In : set set prop term iIn = In infix iIn 2000 2000 const real : set const SNo : set prop axiom real_SNo: !x:set.x iIn real -> SNo x const mul_SNo : set set set term * = mul_SNo infix * 2291 2290 lemma !x:set.!y:set.x iIn real -> y iIn real -> SNo x -> x * y iIn real claim !x:set.x iIn real -> !y:set.y iIn real -> x * y iIn real