const SNo : set prop const mul_SNo : set set set term * = mul_SNo infix * 2291 2290 axiom SNo_mul_SNo: !x:set.!y:set.SNo x -> SNo y -> SNo (x * y) claim !x:set.!y:set.!z:set.SNo x -> SNo y -> SNo z -> SNo (x * y * z)