Consider the TRS R consisting of the rewrite rules

1: 1 . x -> x
2: x . 1 -> x
3: i(x) . x -> 1
4: x . i(x) -> 1
5: i(1) -> 1
6: i(i(x)) -> x
7: i(y) . (y . z) -> z
8: y . (i(y) . z) -> z

There are no dependency pairs.
Hence the TRS is trivially terminating.