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) axiom mul_SNo_com_3_0_1: !x:set.!y:set.!z:set.SNo x -> SNo y -> SNo z -> x * y * z = y * x * z axiom mul_SNo_rotate_3_1: !x:set.!y:set.!z:set.SNo x -> SNo y -> SNo z -> x * y * z = z * x * y claim !x:set.!y:set.!z:set.!w:set.SNo x -> SNo y -> SNo z -> SNo w -> x * y * z * w = w * x * y * z