Certification Problem

Input (TPDB TRS_Standard/SK90/2.02)

The rewrite relation of the following TRS is considered.

+(+(x,y),z) +(x,+(y,z)) (1)
+(f(x),f(y)) f(+(x,y)) (2)
+(f(x),+(f(y),z)) +(f(+(x,y)),z) (3)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by ttt2 @ termCOMP 2023)

1 Rule Removal

Using the Knuth Bendix order with w0 = 1 and the following precedence and weight functions
prec(f) = 0 weight(f) = 1
prec(+) = 1 weight(+) = 0
all of the following rules can be deleted.
+(+(x,y),z) +(x,+(y,z)) (1)
+(f(x),f(y)) f(+(x,y)) (2)
+(f(x),+(f(y),z)) +(f(+(x,y)),z) (3)

1.1 R is empty

There are no rules in the TRS. Hence, it is terminating.