YES Termination Proof

Termination Proof

by ttt2 (version ttt2 1.15)

Input

The rewrite relation of the following TRS is considered.

a(a(x0)) x0
a(b(b(b(x0)))) b(b(b(a(b(a(x0))))))

Proof

1 Dependency Pair Transformation

The following set of initial dependency pairs has been identified.
a#(b(b(b(x0)))) a#(x0)
a#(b(b(b(x0)))) a#(b(a(x0)))

1.1 Reduction Pair Processor with Usable Rules

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the arctic semiring over the integers
[b(x1)] =
-∞ 0 0
0 -∞ 1
0 -∞ -∞
· x1 +
0 -∞ -∞
1 -∞ -∞
0 -∞ -∞
[a(x1)] =
1 0 0
0 -∞ -∞
0 -∞ -∞
· x1 +
1 -∞ -∞
-∞ -∞ -∞
0 -∞ -∞
[a#(x1)] =
0 0 0
-∞ -∞ -∞
-∞ -∞ -∞
· x1 +
-∞ -∞ -∞
-∞ -∞ -∞
-∞ -∞ -∞
together with the usable rules
a(a(x0)) x0
a(b(b(b(x0)))) b(b(b(a(b(a(x0))))))
(w.r.t. the implicit argument filter of the reduction pair), the pair
a#(b(b(b(x0)))) a#(b(a(x0)))
remains.

1.1.1 Reduction Pair Processor with Usable Rules

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the arctic semiring over the integers
[b(x1)] =
-∞ 0 0
0 -∞ -∞
0 1 -∞
· x1 +
0 -∞ -∞
0 -∞ -∞
0 -∞ -∞
[a(x1)] =
1 0 0
0 -∞ -∞
0 -∞ -∞
· x1 +
0 -∞ -∞
0 -∞ -∞
0 -∞ -∞
[a#(x1)] =
0 -∞ -∞
-∞ -∞ -∞
-∞ -∞ -∞
· x1 +
0 -∞ -∞
-∞ -∞ -∞
-∞ -∞ -∞
together with the usable rules
a(a(x0)) x0
a(b(b(b(x0)))) b(b(b(a(b(a(x0))))))
(w.r.t. the implicit argument filter of the reduction pair), all pairs could be removed.

1.1.1.1 P is empty

There are no pairs anymore.