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 when applying the reduction pair processor with usable rules to remove from the DP problem
   pairs:
   
   active#(U11(X)) -> active#(X)
   active#(U12(X)) -> active#(X)
   active#(isNePal(X)) -> active#(X)
   rules:
   
   U11(mark(X)) -> mark(U11(X))
   U11(ok(X)) -> ok(U11(X))
   U12(mark(X)) -> mark(U12(X))
   U12(ok(X)) -> ok(U12(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(U12(tt))
   active(U12(tt)) -> mark(tt)
   active(isNePal(__(I, __(P, I)))) -> mark(U11(tt))
   active(__(X1, X2)) -> __(active(X1), X2)
   active(__(X1, X2)) -> __(X1, active(X2))
   active(U11(X)) -> U11(active(X))
   active(U12(X)) -> U12(active(X))
   active(isNePal(X)) -> isNePal(active(X))
   isNePal(mark(X)) -> mark(isNePal(X))
   isNePal(ok(X)) -> ok(isNePal(X))
   proper(__(X1, X2)) -> __(proper(X1), proper(X2))
   proper(nil) -> ok(nil)
   proper(U11(X)) -> U11(proper(X))
   proper(tt) -> ok(tt)
   proper(U12(X)) -> U12(proper(X))
   proper(isNePal(X)) -> isNePal(proper(X))
   top(mark(X)) -> top(proper(X))
   top(ok(X)) -> top(active(X))
   
    the pairs 
   active#(U12(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(U11/1) = 1
   pi(U12/1) = [1]
   pi(isNePal/1) = 1
   
   RPO with the following precedence
   precedence(active#[1]) = 0
   precedence(U12[1]) = 1
   
   precedence(_) = 0
   and the following status
   status(active#[1]) = lex
   status(U12[1]) = lex
   
   status(_) = lex
   
   problem when orienting DPs
   cannot orient pair active#(U11(X)) -> active#(X) weakly:
   [(active#(U11(X)),0),(U11(X),0)] >=mu [(active#(X),0),(X,0)] could not be ensured