MAYBE MAYBE TRS: { plus(x, 0()) -> x, plus(0(), y) -> y, plus(s(x), y) -> s(plus(x, y)), times(0(), y) -> 0(), times(s(x), y) -> plus(y, times(x, y)), times(s(0()), y) -> y, div(x, y) -> quot(x, y, y), div(0(), y) -> 0(), div(div(x, y), z) -> div(x, times(y, z)), quot(x, 0(), s(z)) -> s(div(x, s(z))), quot(0(), s(y), z) -> 0(), quot(s(x), s(y), z) -> quot(x, y, z) } DUP: We consider a duplicating system. Trs: { plus(x, 0()) -> x, plus(0(), y) -> y, plus(s(x), y) -> s(plus(x, y)), times(0(), y) -> 0(), times(s(x), y) -> plus(y, times(x, y)), times(s(0()), y) -> y, div(x, y) -> quot(x, y, y), div(0(), y) -> 0(), div(div(x, y), z) -> div(x, times(y, z)), quot(x, 0(), s(z)) -> s(div(x, s(z))), quot(0(), s(y), z) -> 0(), quot(s(x), s(y), z) -> quot(x, y, z) } Fail