Certification Problem

Input (COPS 73)

We consider the TRS containing the following rules:

f(g(g(x))) a (1)
f(g(h(x))) b (2)
f(h(g(x))) b (3)
f(h(h(x))) c (4)
g(x) h(x) (5)
a b (6)
b c (7)

The underlying signature is as follows:

{f/1, g/1, a/0, h/1, b/0, c/0}

Property / Task

Prove or disprove confluence.

Answer / Result

Yes.

Proof (by ACP @ CoCo 2020)

1 Strongly closed

Confluence is proven since the TRS is strongly closed. The joins can be performed using 3 step(s).