const SNo : set prop const add_SNo : set set set term + = add_SNo infix + 2281 2280 axiom SNo_add_SNo_3: !x:set.!y:set.!z:set.SNo x -> SNo y -> SNo z -> SNo (x + y + z) axiom add_SNo_com_3_0_1: !x:set.!y:set.!z:set.SNo x -> SNo y -> SNo z -> x + y + z = y + x + z axiom add_SNo_rotate_4_1: !x:set.!y:set.!z:set.!w:set.SNo x -> SNo y -> SNo z -> SNo w -> x + y + z + w = w + x + y + z claim !x:set.!y:set.!z:set.!w:set.!u:set.SNo x -> SNo y -> SNo z -> SNo w -> SNo u -> x + y + z + w + u = u + x + y + z + w