Certification Problem

Input (TPDB SRS_Relative/Waldmann_19/random-24)

The relative rewrite relation R/S is considered where R is the following TRS

c(c(a(x1))) c(a(b(x1))) (1)
b(b(b(x1))) a(a(a(x1))) (2)
b(b(a(x1))) c(c(a(x1))) (3)

and S is the following TRS.

c(a(a(x1))) a(a(a(x1))) (4)
b(c(b(x1))) c(b(a(x1))) (5)
b(a(a(x1))) c(c(c(x1))) (6)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Closure Under Flat Contexts

Using the flat contexts

{c(), a(), b()}

We obtain the transformed TRS
c(c(a(x1))) c(a(b(x1))) (1)
c(b(b(b(x1)))) c(a(a(a(x1)))) (7)
a(b(b(b(x1)))) a(a(a(a(x1)))) (8)
b(b(b(b(x1)))) b(a(a(a(x1)))) (9)
c(b(b(a(x1)))) c(c(c(a(x1)))) (10)
a(b(b(a(x1)))) a(c(c(a(x1)))) (11)
b(b(b(a(x1)))) b(c(c(a(x1)))) (12)
c(c(a(a(x1)))) c(a(a(a(x1)))) (13)
a(c(a(a(x1)))) a(a(a(a(x1)))) (14)
b(c(a(a(x1)))) b(a(a(a(x1)))) (15)
c(b(c(b(x1)))) c(c(b(a(x1)))) (16)
a(b(c(b(x1)))) a(c(b(a(x1)))) (17)
b(b(c(b(x1)))) b(c(b(a(x1)))) (18)
c(b(a(a(x1)))) c(c(c(c(x1)))) (19)
a(b(a(a(x1)))) a(c(c(c(x1)))) (20)
b(b(a(a(x1)))) b(c(c(c(x1)))) (21)

1.1 Semantic Labeling

Root-labeling is applied.

We obtain the labeled TRS
cc(ca(ac(x1))) ca(ab(bc(x1))) (22)
cc(ca(aa(x1))) ca(ab(ba(x1))) (23)
cc(ca(ab(x1))) ca(ab(bb(x1))) (24)
cb(bb(bb(bc(x1)))) ca(aa(aa(ac(x1)))) (25)
cb(bb(bb(ba(x1)))) ca(aa(aa(aa(x1)))) (26)
cb(bb(bb(bb(x1)))) ca(aa(aa(ab(x1)))) (27)
ab(bb(bb(bc(x1)))) aa(aa(aa(ac(x1)))) (28)
ab(bb(bb(ba(x1)))) aa(aa(aa(aa(x1)))) (29)
ab(bb(bb(bb(x1)))) aa(aa(aa(ab(x1)))) (30)
bb(bb(bb(bc(x1)))) ba(aa(aa(ac(x1)))) (31)
bb(bb(bb(ba(x1)))) ba(aa(aa(aa(x1)))) (32)
bb(bb(bb(bb(x1)))) ba(aa(aa(ab(x1)))) (33)
cb(bb(ba(ac(x1)))) cc(cc(ca(ac(x1)))) (34)
cb(bb(ba(aa(x1)))) cc(cc(ca(aa(x1)))) (35)
cb(bb(ba(ab(x1)))) cc(cc(ca(ab(x1)))) (36)
ab(bb(ba(ac(x1)))) ac(cc(ca(ac(x1)))) (37)
ab(bb(ba(aa(x1)))) ac(cc(ca(aa(x1)))) (38)
ab(bb(ba(ab(x1)))) ac(cc(ca(ab(x1)))) (39)
bb(bb(ba(ac(x1)))) bc(cc(ca(ac(x1)))) (40)
bb(bb(ba(aa(x1)))) bc(cc(ca(aa(x1)))) (41)
bb(bb(ba(ab(x1)))) bc(cc(ca(ab(x1)))) (42)
cc(ca(aa(ac(x1)))) ca(aa(aa(ac(x1)))) (43)
cc(ca(aa(aa(x1)))) ca(aa(aa(aa(x1)))) (44)
cc(ca(aa(ab(x1)))) ca(aa(aa(ab(x1)))) (45)
ac(ca(aa(ac(x1)))) aa(aa(aa(ac(x1)))) (46)
ac(ca(aa(aa(x1)))) aa(aa(aa(aa(x1)))) (47)
ac(ca(aa(ab(x1)))) aa(aa(aa(ab(x1)))) (48)
bc(ca(aa(ac(x1)))) ba(aa(aa(ac(x1)))) (49)
bc(ca(aa(aa(x1)))) ba(aa(aa(aa(x1)))) (50)
bc(ca(aa(ab(x1)))) ba(aa(aa(ab(x1)))) (51)
cb(bc(cb(bc(x1)))) cc(cb(ba(ac(x1)))) (52)
cb(bc(cb(ba(x1)))) cc(cb(ba(aa(x1)))) (53)
cb(bc(cb(bb(x1)))) cc(cb(ba(ab(x1)))) (54)
ab(bc(cb(bc(x1)))) ac(cb(ba(ac(x1)))) (55)
ab(bc(cb(ba(x1)))) ac(cb(ba(aa(x1)))) (56)
ab(bc(cb(bb(x1)))) ac(cb(ba(ab(x1)))) (57)
bb(bc(cb(bc(x1)))) bc(cb(ba(ac(x1)))) (58)
bb(bc(cb(ba(x1)))) bc(cb(ba(aa(x1)))) (59)
bb(bc(cb(bb(x1)))) bc(cb(ba(ab(x1)))) (60)
cb(ba(aa(ac(x1)))) cc(cc(cc(cc(x1)))) (61)
cb(ba(aa(aa(x1)))) cc(cc(cc(ca(x1)))) (62)
cb(ba(aa(ab(x1)))) cc(cc(cc(cb(x1)))) (63)
ab(ba(aa(ac(x1)))) ac(cc(cc(cc(x1)))) (64)
ab(ba(aa(aa(x1)))) ac(cc(cc(ca(x1)))) (65)
ab(ba(aa(ab(x1)))) ac(cc(cc(cb(x1)))) (66)
bb(ba(aa(ac(x1)))) bc(cc(cc(cc(x1)))) (67)
bb(ba(aa(aa(x1)))) bc(cc(cc(ca(x1)))) (68)
bb(ba(aa(ab(x1)))) bc(cc(cc(cb(x1)))) (69)

1.1.1 Rule Removal

Using the Knuth Bendix order with w0 = 1 and the following precedence and weight functions
prec(cc) = 7 weight(cc) = 3
prec(ca) = 6 weight(ca) = 4
prec(ac) = 4 weight(ac) = 2
prec(ab) = 5 weight(ab) = 4
prec(bc) = 1 weight(bc) = 1
prec(aa) = 2 weight(aa) = 3
prec(ba) = 0 weight(ba) = 2
prec(bb) = 3 weight(bb) = 3
prec(cb) = 8 weight(cb) = 5
all of the following rules can be deleted.
cc(ca(ac(x1))) ca(ab(bc(x1))) (22)
cc(ca(aa(x1))) ca(ab(ba(x1))) (23)
cc(ca(ab(x1))) ca(ab(bb(x1))) (24)
cb(bb(bb(bc(x1)))) ca(aa(aa(ac(x1)))) (25)
cb(bb(bb(ba(x1)))) ca(aa(aa(aa(x1)))) (26)
cb(bb(bb(bb(x1)))) ca(aa(aa(ab(x1)))) (27)
ab(bb(bb(bc(x1)))) aa(aa(aa(ac(x1)))) (28)
ab(bb(bb(ba(x1)))) aa(aa(aa(aa(x1)))) (29)
ab(bb(bb(bb(x1)))) aa(aa(aa(ab(x1)))) (30)
bb(bb(bb(bc(x1)))) ba(aa(aa(ac(x1)))) (31)
bb(bb(bb(ba(x1)))) ba(aa(aa(aa(x1)))) (32)
bb(bb(bb(bb(x1)))) ba(aa(aa(ab(x1)))) (33)
cb(bb(ba(ac(x1)))) cc(cc(ca(ac(x1)))) (34)
cb(bb(ba(aa(x1)))) cc(cc(ca(aa(x1)))) (35)
cb(bb(ba(ab(x1)))) cc(cc(ca(ab(x1)))) (36)
ab(bb(ba(ac(x1)))) ac(cc(ca(ac(x1)))) (37)
ab(bb(ba(aa(x1)))) ac(cc(ca(aa(x1)))) (38)
ab(bb(ba(ab(x1)))) ac(cc(ca(ab(x1)))) (39)
bb(bb(ba(ac(x1)))) bc(cc(ca(ac(x1)))) (40)
bb(bb(ba(aa(x1)))) bc(cc(ca(aa(x1)))) (41)
bb(bb(ba(ab(x1)))) bc(cc(ca(ab(x1)))) (42)
cc(ca(aa(ac(x1)))) ca(aa(aa(ac(x1)))) (43)
cc(ca(aa(aa(x1)))) ca(aa(aa(aa(x1)))) (44)
cc(ca(aa(ab(x1)))) ca(aa(aa(ab(x1)))) (45)
ac(ca(aa(ac(x1)))) aa(aa(aa(ac(x1)))) (46)
ac(ca(aa(aa(x1)))) aa(aa(aa(aa(x1)))) (47)
ac(ca(aa(ab(x1)))) aa(aa(aa(ab(x1)))) (48)
bc(ca(aa(ac(x1)))) ba(aa(aa(ac(x1)))) (49)
bc(ca(aa(aa(x1)))) ba(aa(aa(aa(x1)))) (50)
bc(ca(aa(ab(x1)))) ba(aa(aa(ab(x1)))) (51)
cb(bc(cb(bc(x1)))) cc(cb(ba(ac(x1)))) (52)
cb(bc(cb(ba(x1)))) cc(cb(ba(aa(x1)))) (53)
cb(bc(cb(bb(x1)))) cc(cb(ba(ab(x1)))) (54)
ab(bc(cb(bc(x1)))) ac(cb(ba(ac(x1)))) (55)
ab(bc(cb(ba(x1)))) ac(cb(ba(aa(x1)))) (56)
ab(bc(cb(bb(x1)))) ac(cb(ba(ab(x1)))) (57)
bb(bc(cb(bc(x1)))) bc(cb(ba(ac(x1)))) (58)
bb(bc(cb(ba(x1)))) bc(cb(ba(aa(x1)))) (59)
bb(bc(cb(bb(x1)))) bc(cb(ba(ab(x1)))) (60)
cb(ba(aa(ac(x1)))) cc(cc(cc(cc(x1)))) (61)
cb(ba(aa(aa(x1)))) cc(cc(cc(ca(x1)))) (62)
cb(ba(aa(ab(x1)))) cc(cc(cc(cb(x1)))) (63)
ab(ba(aa(ac(x1)))) ac(cc(cc(cc(x1)))) (64)
ab(ba(aa(aa(x1)))) ac(cc(cc(ca(x1)))) (65)
ab(ba(aa(ab(x1)))) ac(cc(cc(cb(x1)))) (66)
bb(ba(aa(ac(x1)))) bc(cc(cc(cc(x1)))) (67)
bb(ba(aa(aa(x1)))) bc(cc(cc(ca(x1)))) (68)
bb(ba(aa(ab(x1)))) bc(cc(cc(cb(x1)))) (69)

1.1.1.1 R is empty

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