ceta_eq: termination proof not accepted
1: error below switch to dependency pairs
1.1: error below the dependency graph processor
 1.1.2: error below the reduction pair processor
  1.1.2.1: error below the reduction pair processor
   1.1.2.1.1: error below the reduction pair processor
    1.1.2.1.1.1: error below the reduction pair processor
     1.1.2.1.1.1.1: error below the reduction pair processor
      1.1.2.1.1.1.1.1: error below the reduction pair processor
       1.1.2.1.1.1.1.1.1: error when applying the reduction pair processor with usable rules to remove from the DP problem
        pairs:
        
        active#(U31(X)) -> active#(X)
        active#(U61(X)) -> active#(X)
        active#(U72(X)) -> active#(X)
        rules:
        
        U11(mark(X)) -> mark(U11(X))
        U11(ok(X)) -> ok(U11(X))
        U21(mark(X1), X2) -> mark(U21(X1, X2))
        U21(ok(X1), ok(X2)) -> ok(U21(X1, X2))
        U22(mark(X)) -> mark(U22(X))
        U22(ok(X)) -> ok(U22(X))
        U31(mark(X)) -> mark(U31(X))
        U31(ok(X)) -> ok(U31(X))
        U41(mark(X1), X2) -> mark(U41(X1, X2))
        U41(ok(X1), ok(X2)) -> ok(U41(X1, X2))
        U42(mark(X)) -> mark(U42(X))
        U42(ok(X)) -> ok(U42(X))
        U51(mark(X1), X2) -> mark(U51(X1, X2))
        U51(ok(X1), ok(X2)) -> ok(U51(X1, X2))
        U52(mark(X)) -> mark(U52(X))
        U52(ok(X)) -> ok(U52(X))
        U61(mark(X)) -> mark(U61(X))
        U61(ok(X)) -> ok(U61(X))
        U71(mark(X1), X2) -> mark(U71(X1, X2))
        U71(ok(X1), ok(X2)) -> ok(U71(X1, X2))
        U72(mark(X)) -> mark(U72(X))
        U72(ok(X)) -> ok(U72(X))
        U81(mark(X)) -> mark(U81(X))
        U81(ok(X)) -> ok(U81(X))
        __(mark(X1), X2) -> mark(__(X1, X2))
        __(X1, mark(X2)) -> mark(__(X1, X2))
        __(ok(X1), ok(X2)) -> ok(__(X1, X2))
        active(__(__(X, Y), Z)) -> mark(__(X, __(Y, Z)))
        active(__(X, nil)) -> mark(X)
        active(__(nil, X)) -> mark(X)
        active(U11(tt)) -> mark(tt)
        active(U21(tt, V2)) -> mark(U22(isList(V2)))
        active(U22(tt)) -> mark(tt)
        active(U31(tt)) -> mark(tt)
        active(U41(tt, V2)) -> mark(U42(isNeList(V2)))
        active(U42(tt)) -> mark(tt)
        active(U51(tt, V2)) -> mark(U52(isList(V2)))
        active(U52(tt)) -> mark(tt)
        active(U61(tt)) -> mark(tt)
        active(U71(tt, P)) -> mark(U72(isPal(P)))
        active(U72(tt)) -> mark(tt)
        active(U81(tt)) -> mark(tt)
        active(isList(V)) -> mark(U11(isNeList(V)))
        active(isList(nil)) -> mark(tt)
        active(isList(__(V1, V2))) -> mark(U21(isList(V1), V2))
        active(isNeList(V)) -> mark(U31(isQid(V)))
        active(isNeList(__(V1, V2))) -> mark(U41(isList(V1), V2))
        active(isNeList(__(V1, V2))) -> mark(U51(isNeList(V1), V2))
        active(isNePal(V)) -> mark(U61(isQid(V)))
        active(isNePal(__(I, __(P, I)))) -> mark(U71(isQid(I), P))
        active(isPal(V)) -> mark(U81(isNePal(V)))
        active(isPal(nil)) -> mark(tt)
        active(isQid(a)) -> mark(tt)
        active(isQid(e)) -> mark(tt)
        active(isQid(i)) -> mark(tt)
        active(isQid(o)) -> mark(tt)
        active(isQid(u)) -> mark(tt)
        active(__(X1, X2)) -> __(active(X1), X2)
        active(__(X1, X2)) -> __(X1, active(X2))
        active(U11(X)) -> U11(active(X))
        active(U21(X1, X2)) -> U21(active(X1), X2)
        active(U22(X)) -> U22(active(X))
        active(U31(X)) -> U31(active(X))
        active(U41(X1, X2)) -> U41(active(X1), X2)
        active(U42(X)) -> U42(active(X))
        active(U51(X1, X2)) -> U51(active(X1), X2)
        active(U52(X)) -> U52(active(X))
        active(U61(X)) -> U61(active(X))
        active(U71(X1, X2)) -> U71(active(X1), X2)
        active(U72(X)) -> U72(active(X))
        active(U81(X)) -> U81(active(X))
        isList(ok(X)) -> ok(isList(X))
        isNeList(ok(X)) -> ok(isNeList(X))
        isNePal(ok(X)) -> ok(isNePal(X))
        isPal(ok(X)) -> ok(isPal(X))
        isQid(ok(X)) -> ok(isQid(X))
        proper(__(X1, X2)) -> __(proper(X1), proper(X2))
        proper(nil) -> ok(nil)
        proper(U11(X)) -> U11(proper(X))
        proper(tt) -> ok(tt)
        proper(U21(X1, X2)) -> U21(proper(X1), proper(X2))
        proper(U22(X)) -> U22(proper(X))
        proper(isList(X)) -> isList(proper(X))
        proper(U31(X)) -> U31(proper(X))
        proper(U41(X1, X2)) -> U41(proper(X1), proper(X2))
        proper(U42(X)) -> U42(proper(X))
        proper(isNeList(X)) -> isNeList(proper(X))
        proper(U51(X1, X2)) -> U51(proper(X1), proper(X2))
        proper(U52(X)) -> U52(proper(X))
        proper(U61(X)) -> U61(proper(X))
        proper(U71(X1, X2)) -> U71(proper(X1), proper(X2))
        proper(U72(X)) -> U72(proper(X))
        proper(isPal(X)) -> isPal(proper(X))
        proper(U81(X)) -> U81(proper(X))
        proper(isQid(X)) -> isQid(proper(X))
        proper(isNePal(X)) -> isNePal(proper(X))
        proper(a) -> ok(a)
        proper(e) -> ok(e)
        proper(i) -> ok(i)
        proper(o) -> ok(o)
        proper(u) -> ok(u)
        top(mark(X)) -> top(proper(X))
        top(ok(X)) -> top(active(X))
        
         the pairs 
        active#(U61(X)) -> active#(X)
        
        could not apply the generic root reduction pair processor with the following
        SCNP-version with mu = MS and the level mapping defined by 
        pi(active#) = [(epsilon,0),(1,0)]
        Argument Filter: 
        pi(active#/1) = []
        pi(U31/1) = 1
        pi(U61/1) = [1]
        pi(U72/1) = 1
        
        RPO with the following precedence
        precedence(active#[1]) = 0
        precedence(U61[1]) = 1
        
        precedence(_) = 0
        and the following status
        status(active#[1]) = lex
        status(U61[1]) = lex
        
        status(_) = lex
        
        problem when orienting DPs
        cannot orient pair active#(U31(X)) -> active#(X) weakly:
        [(active#(U31(X)),0),(U31(X),0)] >=mu [(active#(X),0),(X,0)] could not be ensured