Certification Problem

Input (TPDB TRS_Standard/Transformed_CSR_04/ExSec11_1_Luc02a_GM)

The rewrite relation of the following TRS is considered.

a__terms(N) cons(recip(a__sqr(mark(N))),terms(s(N))) (1)
a__sqr(0) 0 (2)
a__sqr(s(X)) s(a__add(a__sqr(mark(X)),a__dbl(mark(X)))) (3)
a__dbl(0) 0 (4)
a__dbl(s(X)) s(s(a__dbl(mark(X)))) (5)
a__add(0,X) mark(X) (6)
a__add(s(X),Y) s(a__add(mark(X),mark(Y))) (7)
a__first(0,X) nil (8)
a__first(s(X),cons(Y,Z)) cons(mark(Y),first(X,Z)) (9)
a__half(0) 0 (10)
a__half(s(0)) 0 (11)
a__half(s(s(X))) s(a__half(mark(X))) (12)
a__half(dbl(X)) mark(X) (13)
mark(terms(X)) a__terms(mark(X)) (14)
mark(sqr(X)) a__sqr(mark(X)) (15)
mark(add(X1,X2)) a__add(mark(X1),mark(X2)) (16)
mark(dbl(X)) a__dbl(mark(X)) (17)
mark(first(X1,X2)) a__first(mark(X1),mark(X2)) (18)
mark(half(X)) a__half(mark(X)) (19)
mark(cons(X1,X2)) cons(mark(X1),X2) (20)
mark(recip(X)) recip(mark(X)) (21)
mark(s(X)) s(mark(X)) (22)
mark(0) 0 (23)
mark(nil) nil (24)
a__terms(X) terms(X) (25)
a__sqr(X) sqr(X) (26)
a__add(X1,X2) add(X1,X2) (27)
a__dbl(X) dbl(X) (28)
a__first(X1,X2) first(X1,X2) (29)
a__half(X) half(X) (30)

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.
a__half#(dbl(X)) mark#(X) (31)
a__terms#(N) mark#(N) (32)
mark#(terms(X)) a__terms#(mark(X)) (33)
a__dbl#(s(X)) mark#(X) (34)
a__add#(s(X),Y) a__add#(mark(X),mark(Y)) (35)
a__add#(s(X),Y) mark#(Y) (36)
a__sqr#(s(X)) a__sqr#(mark(X)) (37)
a__sqr#(s(X)) a__add#(a__sqr(mark(X)),a__dbl(mark(X))) (38)
a__dbl#(s(X)) a__dbl#(mark(X)) (39)
mark#(sqr(X)) mark#(X) (40)
mark#(s(X)) mark#(X) (41)
mark#(sqr(X)) a__sqr#(mark(X)) (42)
a__sqr#(s(X)) mark#(X) (43)
mark#(add(X1,X2)) a__add#(mark(X1),mark(X2)) (44)
mark#(terms(X)) mark#(X) (45)
a__add#(s(X),Y) mark#(X) (46)
mark#(first(X1,X2)) mark#(X1) (47)
a__half#(s(s(X))) mark#(X) (48)
a__terms#(N) a__sqr#(mark(N)) (49)
mark#(add(X1,X2)) mark#(X2) (50)
mark#(first(X1,X2)) mark#(X2) (51)
a__sqr#(s(X)) mark#(X) (43)
mark#(half(X)) a__half#(mark(X)) (52)
mark#(first(X1,X2)) a__first#(mark(X1),mark(X2)) (53)
mark#(recip(X)) mark#(X) (54)
a__sqr#(s(X)) a__dbl#(mark(X)) (55)
mark#(add(X1,X2)) mark#(X1) (56)
mark#(dbl(X)) mark#(X) (57)
a__first#(s(X),cons(Y,Z)) mark#(Y) (58)
a__add#(0,X) mark#(X) (59)
mark#(cons(X1,X2)) mark#(X1) (60)
mark#(dbl(X)) a__dbl#(mark(X)) (61)
a__half#(s(s(X))) a__half#(mark(X)) (62)
mark#(half(X)) mark#(X) (63)

1.1 Dependency Graph Processor

The dependency pairs are split into 1 component.