Certification Problem

Input (COPS 1069)

We consider two TRSs R and S where R contains the rules

+(0,0) 0 (1)
+(s(x),y) s(+(x,y)) (2)
+(x,s(y)) s(+(y,x)) (3)

and S contains the following rules:

+(0,y) y (4)
+(s(x),y) s(+(y,x)) (5)
+(x,y) +(y,x) (6)

The underlying signature is as follows:

{+/2, 0/0, s/1}

Property / Task

Prove or disprove commutation.

Answer / Result

Yes.

Proof (by ACP @ CoCo 2023)

1 Swap TRSs

The role of TRSs R and S are changed.

1.1 Development Closed

Commutation is proven since the TRSs are development closed. The joins can be performed using 5 step(s).