Certification Problem

Input (TPDB TRS_Standard/Various_04/24)

The rewrite relation of the following TRS is considered.

max(L(x)) x (1)
max(N(L(0),L(y))) y (2)
max(N(L(s(x)),L(s(y)))) s(max(N(L(x),L(y)))) (3)
max(N(L(x),N(y,z))) max(N(L(x),L(max(N(y,z))))) (4)

Property / Task

Prove or disprove termination.

Answer / Result

Yes.

Proof (by ttt2 @ termCOMP 2023)

1 Rule Removal

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the naturals
[s(x1)] =
1 0 0
0 1 0
1 1 0
· x1 +
0 0 0
0 0 0
0 0 0
[max(x1)] =
1 0 0
1 0 0
0 1 0
· x1 +
0 0 0
1 0 0
0 0 0
[N(x1, x2)] =
1 0 0
1 1 0
1 0 0
· x1 +
1 0 1
1 1 1
1 1 1
· x2 +
0 0 0
1 0 0
1 0 0
[L(x1)] =
1 1 0
0 0 1
0 0 0
· x1 +
0 0 0
0 0 0
0 0 0
[0] =
1 0 0
1 0 0
0 0 0
all of the following rules can be deleted.
max(N(L(0),L(y))) y (2)

1.1 Rule Removal

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the naturals
[s(x1)] =
1 0 1
0 0 1
0 0 1
· x1 +
1 0 0
0 0 0
0 0 0
[max(x1)] =
1 0 0
0 0 1
0 0 1
· x1 +
0 0 0
0 0 0
0 0 0
[N(x1, x2)] =
1 0 0
1 0 0
0 0 0
· x1 +
1 1 0
1 1 0
0 0 0
· x2 +
1 0 0
0 0 0
0 0 0
[L(x1)] =
1 0 1
0 0 0
1 1 1
· x1 +
0 0 0
0 0 0
0 0 0
all of the following rules can be deleted.
max(N(L(s(x)),L(s(y)))) s(max(N(L(x),L(y)))) (3)

1.1.1 Rule Removal

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the naturals
[max(x1)] =
1 0 0
1 0 0
0 0 1
· x1 +
0 0 0
0 0 0
0 0 0
[N(x1, x2)] =
1 1 0
1 1 0
0 0 0
· x1 +
1 1 0
1 1 0
0 0 0
· x2 +
0 0 0
1 0 0
0 0 0
[L(x1)] =
1 1 0
0 0 0
1 0 1
· x1 +
1 0 0
0 0 0
0 0 0
all of the following rules can be deleted.
max(L(x)) x (1)

1.1.1.1 Rule Removal

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the naturals
[max(x1)] =
1 0 0
0 1 0
0 0 0
· x1 +
0 0 0
0 0 0
0 0 0
[N(x1, x2)] =
1 0 0
1 0 1
0 0 0
· x1 +
1 1 0
0 0 0
0 0 0
· x2 +
0 0 0
1 0 0
0 0 0
[L(x1)] =
1 0 0
0 0 0
1 0 0
· x1 +
0 0 0
0 0 0
1 0 0
all of the following rules can be deleted.
max(N(L(x),N(y,z))) max(N(L(x),L(max(N(y,z))))) (4)

1.1.1.1.1 R is empty

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