Certification Problem

Input (TPDB TRS_Standard/SK90/2.45)

The rewrite relation of the following TRS is considered.

admit(x,nil) nil (1)
admit(x,.(u,.(v,.(w,z)))) cond(=(sum(x,u,v),w),.(u,.(v,.(w,admit(carry(x,u,v),z))))) (2)
cond(true,y) y (3)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

Using the
prec(admit) = 5 stat(admit) = lex
prec(nil) = 1 stat(nil) = mul
prec(.) = 5 stat(.) = lex
prec(w) = 0 stat(w) = mul
prec(cond) = 2 stat(cond) = lex
prec(=) = 3 stat(=) = mul
prec(sum) = 4 stat(sum) = lex
prec(carry) = 0 stat(carry) = mul
prec(true) = 6 stat(true) = mul

π(admit) = [2,1]
π(nil) = []
π(.) = [1,2]
π(w) = []
π(cond) = [2,1]
π(=) = [1,2]
π(sum) = [1,3,2]
π(carry) = [1,2,3]
π(true) = []

all of the following rules can be deleted.
admit(x,nil) nil (1)
admit(x,.(u,.(v,.(w,z)))) cond(=(sum(x,u,v),w),.(u,.(v,.(w,admit(carry(x,u,v),z))))) (2)
cond(true,y) y (3)

1.1 R is empty

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