Termination w.r.t. Q of the following Term Rewriting System could be proven:

Q restricted rewrite system:
The TRS R consists of the following rules:

app2(app2(app2(comp, f), g), x) -> app2(f, app2(g, x))
app2(twice, f) -> app2(app2(comp, f), f)

Q is empty.


↳ QTRS
  ↳ DependencyPairsProof

Q restricted rewrite system:
The TRS R consists of the following rules:

app2(app2(app2(comp, f), g), x) -> app2(f, app2(g, x))
app2(twice, f) -> app2(app2(comp, f), f)

Q is empty.

Using Dependency Pairs [1,13] we result in the following initial DP problem:
Q DP problem:
The TRS P consists of the following rules:

APP2(twice, f) -> APP2(comp, f)
APP2(twice, f) -> APP2(app2(comp, f), f)
APP2(app2(app2(comp, f), g), x) -> APP2(f, app2(g, x))
APP2(app2(app2(comp, f), g), x) -> APP2(g, x)

The TRS R consists of the following rules:

app2(app2(app2(comp, f), g), x) -> app2(f, app2(g, x))
app2(twice, f) -> app2(app2(comp, f), f)

Q is empty.
We have to consider all minimal (P,Q,R)-chains.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof

Q DP problem:
The TRS P consists of the following rules:

APP2(twice, f) -> APP2(comp, f)
APP2(twice, f) -> APP2(app2(comp, f), f)
APP2(app2(app2(comp, f), g), x) -> APP2(f, app2(g, x))
APP2(app2(app2(comp, f), g), x) -> APP2(g, x)

The TRS R consists of the following rules:

app2(app2(app2(comp, f), g), x) -> app2(f, app2(g, x))
app2(twice, f) -> app2(app2(comp, f), f)

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
The approximation of the Dependency Graph [13,14,18] contains 1 SCC with 2 less nodes.

↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ QDP
          ↳ QDPOrderProof

Q DP problem:
The TRS P consists of the following rules:

APP2(app2(app2(comp, f), g), x) -> APP2(f, app2(g, x))
APP2(app2(app2(comp, f), g), x) -> APP2(g, x)

The TRS R consists of the following rules:

app2(app2(app2(comp, f), g), x) -> app2(f, app2(g, x))
app2(twice, f) -> app2(app2(comp, f), f)

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We use the reduction pair processor [13].


The following pairs can be oriented strictly and are deleted.


APP2(app2(app2(comp, f), g), x) -> APP2(f, app2(g, x))
APP2(app2(app2(comp, f), g), x) -> APP2(g, x)
The remaining pairs can at least be oriented weakly.
none
Used ordering: Polynomial Order [17,21] with Interpretation:

POL( comp ) = 2


POL( twice ) = 2


POL( APP2(x1, x2) ) = max{0, x1 - 3}


POL( app2(x1, x2) ) = x1 + x2 + 3



The following usable rules [14] were oriented: none



↳ QTRS
  ↳ DependencyPairsProof
    ↳ QDP
      ↳ DependencyGraphProof
        ↳ QDP
          ↳ QDPOrderProof
            ↳ QDP
              ↳ PisEmptyProof

Q DP problem:
P is empty.
The TRS R consists of the following rules:

app2(app2(app2(comp, f), g), x) -> app2(f, app2(g, x))
app2(twice, f) -> app2(app2(comp, f), f)

Q is empty.
We have to consider all minimal (P,Q,R)-chains.
The TRS P is empty. Hence, there is no (P,Q,R) chain.