import algebra.ring data.num open algebra variable A : Type variable s : ring A variable H0 : 0 = (0:A) -- since algebra defines notation '0' it should have precedence over num variable H1 : 1 = (1:A) -- since algebra defines notation '1' it should have precedence over num example : has_zero.zero A = has_zero.zero A := H0 example : has_one.one A = has_one.one A := H1