Certification Problem

Input (TPDB TRS_Standard/SK90/4.10)

The rewrite relation of the following TRS is considered.

*(x,*(y,z)) *(otimes(x,y),z) (1)
*(1,y) y (2)
*(+(x,y),z) oplus(*(x,z),*(y,z)) (3)
*(x,oplus(y,z)) oplus(*(x,y),*(x,z)) (4)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

Using the
prec(*) = 2 stat(*) = lex
prec(otimes) = 0 stat(otimes) = mul
prec(1) = 3 stat(1) = mul
prec(+) = 4 stat(+) = lex
prec(oplus) = 1 stat(oplus) = lex

π(*) = [2,1]
π(otimes) = [1,2]
π(1) = []
π(+) = [1,2]
π(oplus) = [2,1]

all of the following rules can be deleted.
*(x,*(y,z)) *(otimes(x,y),z) (1)
*(1,y) y (2)
*(+(x,y),z) oplus(*(x,z),*(y,z)) (3)
*(x,oplus(y,z)) oplus(*(x,y),*(x,z)) (4)

1.1 R is empty

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