(0) Obligation:

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

f(g(i(a, b, b'), c), d) → if(e, f(.(b, c), d'), f(.(b', c), d'))
f(g(h(a, b), c), d) → if(e, f(.(b, g(h(a, b), c)), d), f(c, d'))

Q is empty.

(1) QTRSRRRProof (EQUIVALENT transformation)

Used ordering:
Polynomial interpretation [POLO]:

POL(.(x1, x2)) = x1 + x2   
POL(a) = 0   
POL(b) = 0   
POL(b') = 0   
POL(c) = 0   
POL(d) = 0   
POL(d') = 0   
POL(e) = 0   
POL(f(x1, x2)) = x1 + x2   
POL(g(x1, x2)) = 1 + x1 + x2   
POL(h(x1, x2)) = x1 + x2   
POL(i(x1, x2, x3)) = x1 + x2 + x3   
POL(if(x1, x2, x3)) = x1 + x2 + x3   
With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly:

f(g(i(a, b, b'), c), d) → if(e, f(.(b, c), d'), f(.(b', c), d'))


(2) Obligation:

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

f(g(h(a, b), c), d) → if(e, f(.(b, g(h(a, b), c)), d), f(c, d'))

Q is empty.

(3) Overlay + Local Confluence (EQUIVALENT transformation)

The TRS is overlay and locally confluent. By [NOC] we can switch to innermost.

(4) Obligation:

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

f(g(h(a, b), c), d) → if(e, f(.(b, g(h(a, b), c)), d), f(c, d'))

The set Q consists of the following terms:

f(g(h(a, b), c), d)

(5) DependencyPairsProof (EQUIVALENT transformation)

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

(6) Obligation:

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

F(g(h(a, b), c), d) → F(.(b, g(h(a, b), c)), d)
F(g(h(a, b), c), d) → F(c, d')

The TRS R consists of the following rules:

f(g(h(a, b), c), d) → if(e, f(.(b, g(h(a, b), c)), d), f(c, d'))

The set Q consists of the following terms:

f(g(h(a, b), c), d)

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

(7) DependencyGraphProof (EQUIVALENT transformation)

The approximation of the Dependency Graph [LPAR04,FROCOS05,EDGSTAR] contains 0 SCCs with 2 less nodes.

(8) TRUE