Certification Problem

Input (TPDB TRS_Standard/SK90/2.10)

The rewrite relation of the following TRS is considered.

minus(0) 0 (1)
+(x,0) x (2)
+(0,y) y (3)
+(minus(1),1) 0 (4)
minus(minus(x)) x (5)
+(x,minus(y)) minus(+(minus(x),y)) (6)
+(x,+(y,z)) +(+(x,y),z) (7)
+(minus(+(x,1)),1) minus(x) (8)

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
[minus(x1)] =
1 0 0
0 0 1
0 1 0
· x1 +
0 0 0
0 0 0
0 0 0
[1] =
0 0 0
0 0 0
1 0 0
[0] =
0 0 0
0 0 0
0 0 0
[+(x1, x2)] =
1 0 0
0 1 0
0 0 1
· x1 +
1 1 1
0 1 1
0 1 1
· x2 +
0 0 0
0 0 0
0 0 0
all of the following rules can be deleted.
+(minus(1),1) 0 (4)
+(minus(+(x,1)),1) minus(x) (8)

1.1 Rule Removal

Using the linear polynomial interpretation over (4 x 4)-matrices with strict dimension 1 over the naturals
[minus(x1)] =
1 0 0 0
0 0 0 1
0 0 1 0
0 1 0 0
· x1 +
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
[0] =
0 0 0 0
0 0 0 0
1 0 0 0
0 0 0 0
[+(x1, x2)] =
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1
· x1 +
1 0 1 0
0 1 0 0
0 1 1 1
0 0 0 1
· x2 +
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
all of the following rules can be deleted.
+(x,0) x (2)

1.1.1 Rule Removal

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

1.1.1.1 Rule Removal

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the naturals
[minus(x1)] =
1 0 0
0 1 0
0 0 1
· x1 +
0 0 0
0 0 0
0 0 0
[0] =
0 0 0
0 0 0
0 0 0
[+(x1, x2)] =
1 0 0
0 0 1
0 0 1
· x1 +
1 0 1
0 0 1
0 0 1
· x2 +
0 0 0
0 0 0
1 0 0
all of the following rules can be deleted.
+(x,+(y,z)) +(+(x,y),z) (7)

1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the naturals
[minus(x1)] =
1 0 0
0 0 1
0 1 0
· x1 +
0 0 0
0 0 0
1 0 0
[0] =
1 0 0
0 0 0
0 0 0
[+(x1, x2)] =
1 0 0
0 0 0
0 0 0
· x1 +
1 1 1
0 1 0
0 0 1
· x2 +
1 0 0
0 0 0
0 0 0
all of the following rules can be deleted.
+(x,minus(y)) minus(+(minus(x),y)) (6)

1.1.1.1.1.1 Rule Removal

Using the Weighted Path Order with the following precedence and status
prec(minus) = 0 status(minus) = [1] list-extension(minus) = Lex
prec(0) = 0 status(0) = [] list-extension(0) = Lex
and the following Max-polynomial interpretation
[minus(x1)] = max(0, 0 + 1 · x1)
[0] = max(0)
all of the following rules can be deleted.
minus(0) 0 (1)
minus(minus(x)) x (5)

1.1.1.1.1.1.1 R is empty

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