Certification Problem

Input (TPDB TRS_Standard/TCT_12/recursion-10)

The rewrite relation of the following TRS is considered.

f_0(x) a (1)
f_1(x) g_1(x,x) (2)
g_1(s(x),y) b(f_0(y),g_1(x,y)) (3)
f_2(x) g_2(x,x) (4)
g_2(s(x),y) b(f_1(y),g_2(x,y)) (5)
f_3(x) g_3(x,x) (6)
g_3(s(x),y) b(f_2(y),g_3(x,y)) (7)
f_4(x) g_4(x,x) (8)
g_4(s(x),y) b(f_3(y),g_4(x,y)) (9)
f_5(x) g_5(x,x) (10)
g_5(s(x),y) b(f_4(y),g_5(x,y)) (11)
f_6(x) g_6(x,x) (12)
g_6(s(x),y) b(f_5(y),g_6(x,y)) (13)
f_7(x) g_7(x,x) (14)
g_7(s(x),y) b(f_6(y),g_7(x,y)) (15)
f_8(x) g_8(x,x) (16)
g_8(s(x),y) b(f_7(y),g_8(x,y)) (17)
f_9(x) g_9(x,x) (18)
g_9(s(x),y) b(f_8(y),g_9(x,y)) (19)
f_10(x) g_10(x,x) (20)
g_10(s(x),y) b(f_9(y),g_10(x,y)) (21)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by AProVE @ termCOMP 2023)

1 Rule Removal

Using the
prec(f_0) = 0 stat(f_0) = mul
prec(a) = 0 stat(a) = mul
prec(f_1) = 3 stat(f_1) = mul
prec(g_1) = 2 stat(g_1) = mul
prec(s) = 6 stat(s) = mul
prec(b) = 1 stat(b) = mul
prec(f_2) = 4 stat(f_2) = mul
prec(g_2) = 3 stat(g_2) = mul
prec(f_3) = 5 stat(f_3) = mul
prec(g_3) = 4 stat(g_3) = mul
prec(f_4) = 7 stat(f_4) = mul
prec(g_4) = 5 stat(g_4) = mul
prec(f_5) = 8 stat(f_5) = mul
prec(g_5) = 7 stat(g_5) = mul
prec(f_6) = 9 stat(f_6) = mul
prec(g_6) = 8 stat(g_6) = mul
prec(f_7) = 10 stat(f_7) = mul
prec(g_7) = 9 stat(g_7) = mul
prec(f_8) = 11 stat(f_8) = mul
prec(g_8) = 10 stat(g_8) = mul
prec(f_9) = 13 stat(f_9) = mul
prec(g_9) = 12 stat(g_9) = mul
prec(f_10) = 14 stat(f_10) = mul
prec(g_10) = 13 stat(g_10) = mul

π(f_0) = [1]
π(a) = []
π(f_1) = [1]
π(g_1) = [1,2]
π(s) = [1]
π(b) = [1,2]
π(f_2) = [1]
π(g_2) = [1,2]
π(f_3) = [1]
π(g_3) = [1,2]
π(f_4) = [1]
π(g_4) = [1,2]
π(f_5) = [1]
π(g_5) = [1,2]
π(f_6) = [1]
π(g_6) = [1,2]
π(f_7) = [1]
π(g_7) = [1,2]
π(f_8) = [1]
π(g_8) = [1,2]
π(f_9) = [1]
π(g_9) = [1,2]
π(f_10) = [1]
π(g_10) = [1,2]

all of the following rules can be deleted.
f_0(x) a (1)
f_1(x) g_1(x,x) (2)
g_1(s(x),y) b(f_0(y),g_1(x,y)) (3)
f_2(x) g_2(x,x) (4)
g_2(s(x),y) b(f_1(y),g_2(x,y)) (5)
f_3(x) g_3(x,x) (6)
g_3(s(x),y) b(f_2(y),g_3(x,y)) (7)
f_4(x) g_4(x,x) (8)
g_4(s(x),y) b(f_3(y),g_4(x,y)) (9)
f_5(x) g_5(x,x) (10)
g_5(s(x),y) b(f_4(y),g_5(x,y)) (11)
f_6(x) g_6(x,x) (12)
g_6(s(x),y) b(f_5(y),g_6(x,y)) (13)
f_7(x) g_7(x,x) (14)
g_7(s(x),y) b(f_6(y),g_7(x,y)) (15)
f_8(x) g_8(x,x) (16)
g_8(s(x),y) b(f_7(y),g_8(x,y)) (17)
f_9(x) g_9(x,x) (18)
g_9(s(x),y) b(f_8(y),g_9(x,y)) (19)
f_10(x) g_10(x,x) (20)
g_10(s(x),y) b(f_9(y),g_10(x,y)) (21)

1.1 R is empty

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