Certification Problem

Input (TPDB TRS_Standard/SK90/2.06)

The rewrite relation of the following TRS is considered.

+(x,+(y,z)) +(+(x,y),z) (1)
+(*(x,y),+(x,z)) *(x,+(y,z)) (2)
+(*(x,y),+(*(x,z),u)) +(*(x,+(y,z)),u) (3)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

Using the linear polynomial interpretation over the naturals
[+(x1, x2)] = 1 + 1 · x1 + 2 · x2
[*(x1, x2)] = 2 + 1 · x1 + 1 · x2
all of the following rules can be deleted.
+(x,+(y,z)) +(+(x,y),z) (1)
+(*(x,y),+(x,z)) *(x,+(y,z)) (2)
+(*(x,y),+(*(x,z),u)) +(*(x,+(y,z)),u) (3)

1.1 R is empty

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