Certification Problem

Input (COPS 333)

The rewrite relation of the following conditional TRS is considered.

f(x) g(x,y,z) | h(a,x) ≈ i(y), h(a,y) ≈ i(z)
h(a,a) i(b)
h(a,b) i(c)
h(b,b) i(d)

Property / Task

Prove or disprove confluence.

Answer / Result

Yes.

Proof (by ConCon @ CoCo 2020)

1 Almost-orthogonal

The given (extended) properly oriented, right-stable, oriented 3-CTRS is almost-orthogonal, since there are no conditional critical pairs.