Term Rewriting System R:
[X, Y, Z, X1, X2]
a2nd(cons(X, cons(Y, Z))) -> mark(Y)
a2nd(X) -> 2nd(X)
afrom(X) -> cons(mark(X), from(s(X)))
afrom(X) -> from(X)
mark(2nd(X)) -> a2nd(mark(X))
mark(from(X)) -> afrom(mark(X))
mark(cons(X1, X2)) -> cons(mark(X1), X2)
mark(s(X)) -> s(mark(X))

Innermost Termination of R to be shown.



   R
Dependency Pair Analysis



R contains the following Dependency Pairs:

A2ND(cons(X, cons(Y, Z))) -> MARK(Y)
AFROM(X) -> MARK(X)
MARK(2nd(X)) -> A2ND(mark(X))
MARK(2nd(X)) -> MARK(X)
MARK(from(X)) -> AFROM(mark(X))
MARK(from(X)) -> MARK(X)
MARK(cons(X1, X2)) -> MARK(X1)
MARK(s(X)) -> MARK(X)

Furthermore, R contains one SCC.


   R
DPs
       →DP Problem 1
Narrowing Transformation


Dependency Pairs:

MARK(s(X)) -> MARK(X)
MARK(cons(X1, X2)) -> MARK(X1)
MARK(from(X)) -> MARK(X)
AFROM(X) -> MARK(X)
MARK(from(X)) -> AFROM(mark(X))
MARK(2nd(X)) -> MARK(X)
MARK(2nd(X)) -> A2ND(mark(X))
A2ND(cons(X, cons(Y, Z))) -> MARK(Y)


Rules:


a2nd(cons(X, cons(Y, Z))) -> mark(Y)
a2nd(X) -> 2nd(X)
afrom(X) -> cons(mark(X), from(s(X)))
afrom(X) -> from(X)
mark(2nd(X)) -> a2nd(mark(X))
mark(from(X)) -> afrom(mark(X))
mark(cons(X1, X2)) -> cons(mark(X1), X2)
mark(s(X)) -> s(mark(X))


Strategy:

innermost




On this DP problem, a Narrowing SCC transformation can be performed.
As a result of transforming the rule

MARK(2nd(X)) -> A2ND(mark(X))
four new Dependency Pairs are created:

MARK(2nd(2nd(X''))) -> A2ND(a2nd(mark(X'')))
MARK(2nd(from(X''))) -> A2ND(afrom(mark(X'')))
MARK(2nd(cons(X1', X2'))) -> A2ND(cons(mark(X1'), X2'))
MARK(2nd(s(X''))) -> A2ND(s(mark(X'')))

The transformation is resulting in one new DP problem:



   R
DPs
       →DP Problem 1
Nar
           →DP Problem 2
Remaining Obligation(s)




The following remains to be proven:
Dependency Pairs:

MARK(2nd(cons(X1', X2'))) -> A2ND(cons(mark(X1'), X2'))
MARK(2nd(from(X''))) -> A2ND(afrom(mark(X'')))
A2ND(cons(X, cons(Y, Z))) -> MARK(Y)
MARK(2nd(2nd(X''))) -> A2ND(a2nd(mark(X'')))
MARK(cons(X1, X2)) -> MARK(X1)
MARK(from(X)) -> MARK(X)
AFROM(X) -> MARK(X)
MARK(from(X)) -> AFROM(mark(X))
MARK(2nd(X)) -> MARK(X)
MARK(s(X)) -> MARK(X)


Rules:


a2nd(cons(X, cons(Y, Z))) -> mark(Y)
a2nd(X) -> 2nd(X)
afrom(X) -> cons(mark(X), from(s(X)))
afrom(X) -> from(X)
mark(2nd(X)) -> a2nd(mark(X))
mark(from(X)) -> afrom(mark(X))
mark(cons(X1, X2)) -> cons(mark(X1), X2)
mark(s(X)) -> s(mark(X))


Strategy:

innermost



The Proof could not be continued due to a Timeout.
Innermost Termination of R could not be shown.
Duration:
1:00 minutes