Certification Problem

Input (TPDB TRS_Standard/SK90/4.11)

The rewrite relation of the following TRS is considered.

+(x,0) x (1)
+(x,s(y)) s(+(x,y)) (2)
+(0,s(y)) s(y) (3)
s(+(0,y)) s(y) (4)

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(s) = 0 weight(s) = 4
prec(+) = 1 weight(+) = 0
prec(0) = 2 weight(0) = 2
all of the following rules can be deleted.
+(x,0) x (1)
+(x,s(y)) s(+(x,y)) (2)
+(0,s(y)) s(y) (3)
s(+(0,y)) s(y) (4)

1.1 R is empty

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