Certification Problem

Input (TPDB TRS_Standard/Rubio_04/prov)

The rewrite relation of the following TRS is considered.

ackin(s(X),s(Y)) u21(ackin(s(X),Y),X) (1)
u21(ackout(X),Y) u22(ackin(Y,X)) (2)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

Using the
prec(ackin) = 1 stat(ackin) = lex
prec(s) = 0 stat(s) = lex
prec(u21) = 1 stat(u21) = lex

π(ackin) = [1,2]
π(s) = [1]
π(u21) = [2,1]
π(ackout) = 1
π(u22) = 1

all of the following rules can be deleted.
ackin(s(X),s(Y)) u21(ackin(s(X),Y),X) (1)

1.1 Rule Removal

Using the Knuth Bendix order with w0 = 1 and the following precedence and weight functions
prec(ackout) = 0 weight(ackout) = 1
prec(u22) = 1 weight(u22) = 1
prec(u21) = 2 weight(u21) = 0
prec(ackin) = 3 weight(ackin) = 0
all of the following rules can be deleted.
u21(ackout(X),Y) u22(ackin(Y,X)) (2)

1.1.1 R is empty

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