Certification Problem

Input (COPS 150)

We consider the TRS containing the following rules:

f(0,0) f(0,1) (1)
f(1,0) f(0,0) (2)
f(x,y) f(y,x) (3)

The underlying signature is as follows:

{f/2, 0/0, 1/0}

Property / Task

Prove or disprove confluence.

Answer / Result

Yes.

Proof (by csi @ CoCo 2020)

1 Redundant Rules Transformation

To prove that the TRS is (non-)confluent, we show (non-)confluence of the following modified system:

f(x,y) f(y,x) (3)
f(1,0) f(0,0) (2)
f(0,0) f(0,1) (1)
f(x,y) f(x,y) (4)
f(1,0) f(0,1) (5)
f(0,0) f(1,0) (6)

All redundant rules that were added or removed can be simulated in 2 steps .

1.1 Parallel Closed

Confluence is proven since the TRS is (almost) parallel closed. The joins can be performed using 1 parallel step(s).