YES Termination Proof

Termination Proof

by ttt2 (version ttt2 1.15)

Input

The rewrite relation of the following TRS is considered.

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

Proof

1 Rule Removal

Using the linear polynomial interpretation over (3 x 3)-matrices with strict dimension 1 over the arctic semiring over the integers
[b(x1)] =
0 1 -∞
-∞ 0 -∞
0 1 0
· x1 +
-∞ -∞ -∞
-∞ -∞ -∞
-∞ -∞ -∞
[a(x1)] =
0 0 1
0 0 0
-∞ 0 0
· x1 +
-∞ -∞ -∞
-∞ -∞ -∞
-∞ -∞ -∞
the rules
a(x0) x0
b(a(a(b(x0)))) a(a(a(a(b(b(b(x0)))))))
a(a(a(a(x0)))) b(x0)
remain.

1.1 Dependency Pair Transformation

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

1.1.1 Reduction Pair Processor with Usable Rules

Using the linear polynomial interpretation over (4 x 4)-matrices with strict dimension 1 over the arctic semiring over the integers
[b(x1)] =
0 0 0 0
-∞ -∞ 0 0
0 0 0 0
0 0 0 0
· x1 +
0 -∞ -∞ -∞
0 -∞ -∞ -∞
0 -∞ -∞ -∞
0 -∞ -∞ -∞
[b#(x1)] =
0 0 0 0
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
· x1 +
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
[a(x1)] =
0 0 -∞ 0
0 0 0 0
0 0 0 1
0 -∞ -∞ 0
· x1 +
-∞ -∞ -∞ -∞
0 -∞ -∞ -∞
0 -∞ -∞ -∞
0 -∞ -∞ -∞
[a#(x1)] =
0 0 0 1
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
· x1 +
0 -∞ -∞ -∞
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
-∞ -∞ -∞ -∞
together with the usable rules
a(x0) x0
b(a(a(b(x0)))) a(a(a(a(b(b(b(x0)))))))
a(a(a(a(x0)))) b(x0)
(w.r.t. the implicit argument filter of the reduction pair), the pairs
b#(a(a(b(x0)))) a#(b(b(b(x0))))
b#(a(a(b(x0)))) a#(a(b(b(b(x0)))))
b#(a(a(b(x0)))) a#(a(a(b(b(b(x0))))))
b#(a(a(b(x0)))) a#(a(a(a(b(b(b(x0)))))))
remain.

1.1.1.1 Dependency Graph Processor

The dependency pairs are split into 0 components.