Certification Problem

Input (TPDB TRS_Standard/Transformed_CSR_04/Ex1_Luc02b_FR)

The rewrite relation of the following TRS is considered.

from(X) cons(X,n__from(n__s(X))) (1)
first(0,Z) nil (2)
first(s(X),cons(Y,Z)) cons(Y,n__first(X,activate(Z))) (3)
sel(0,cons(X,Z)) X (4)
sel(s(X),cons(Y,Z)) sel(X,activate(Z)) (5)
from(X) n__from(X) (6)
s(X) n__s(X) (7)
first(X1,X2) n__first(X1,X2) (8)
activate(n__from(X)) from(activate(X)) (9)
activate(n__s(X)) s(activate(X)) (10)
activate(n__first(X1,X2)) first(activate(X1),activate(X2)) (11)
activate(X) X (12)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by NaTT @ termCOMP 2023)

1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
activate#(n__from(X)) activate#(X) (13)
activate#(n__s(X)) s#(activate(X)) (14)
sel#(s(X),cons(Y,Z)) activate#(Z) (15)
activate#(n__s(X)) activate#(X) (16)
first#(s(X),cons(Y,Z)) activate#(Z) (17)
activate#(n__first(X1,X2)) activate#(X2) (18)
activate#(n__first(X1,X2)) first#(activate(X1),activate(X2)) (19)
activate#(n__from(X)) from#(activate(X)) (20)
sel#(s(X),cons(Y,Z)) sel#(X,activate(Z)) (21)
activate#(n__first(X1,X2)) activate#(X1) (22)

1.1 Dependency Graph Processor

The dependency pairs are split into 2 components.