(0) Obligation:

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

ap(ap(g, x), y) → y
ap(f, x) → ap(f, app(g, x))

Q is empty.

(1) QTRSRRRProof (EQUIVALENT transformation)

Used ordering:
Polynomial interpretation [POLO]:

POL(ap(x1, x2)) = 1 + 2·x1 + 2·x2   
POL(app(x1, x2)) = x1 + x2   
POL(f) = 0   
POL(g) = 0   
With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly:

ap(ap(g, x), y) → y


(2) Obligation:

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

ap(f, x) → ap(f, app(g, x))

Q is empty.

(3) DependencyPairsProof (EQUIVALENT transformation)

Using Dependency Pairs [AG00,LPAR04] we result in the following initial DP problem.

(4) Obligation:

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

AP(f, x) → AP(f, app(g, x))

The TRS R consists of the following rules:

ap(f, x) → ap(f, app(g, x))

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

(5) NonLoopProof (EQUIVALENT transformation)

By Theorem 8 [NONLOOP] we deduce infiniteness of the QDP.
We apply the theorem with m = 1, b = 0,
σ' = [ ], and μ' = [x0 / app(g, x0)] on the rule
AP(f, app(g, x0))[ ]n[ ] → AP(f, app(g, x0))[ ]n[x0 / app(g, x0)]
This rule is correct for the QDP as the following derivation shows:

intermediate steps: Equivalent (Simplify mu) - Instantiate mu - Instantiation
AP(f, x)[ ]n[ ] → AP(f, app(g, x))[ ]n[ ]
    by OriginalRule from TRS P

(6) NO