const SNo : set prop const ordsucc : set set const Empty : set axiom SNo_1: SNo (ordsucc Empty) const mul_SNo : set set set term * = mul_SNo infix * 2291 2290 axiom mul_SNo_oneR: !x:set.SNo x -> x * ordsucc Empty = x axiom mul_SNo_com: !x:set.!y:set.SNo x -> SNo y -> x * y = y * x claim !x:set.SNo x -> ordsucc Empty * x = x