ceta_eq: termination proof not accepted
1: error below switch to dependency pairs
1.1: error below the dependency graph processor
 1.1.5: error when applying the reduction pair processor with usable rules to remove from the DP problem
  pairs:
  
  plus#(mark(X1), X2) -> plus#(X1, X2)
  plus#(X1, mark(X2)) -> plus#(X1, X2)
  plus#(active(X1), X2) -> plus#(X1, X2)
  plus#(X1, active(X2)) -> plus#(X1, X2)
  rules:
  
  U11(mark(X1), X2, X3) -> U11(X1, X2, X3)
  U11(X1, mark(X2), X3) -> U11(X1, X2, X3)
  U11(X1, X2, mark(X3)) -> U11(X1, X2, X3)
  U11(active(X1), X2, X3) -> U11(X1, X2, X3)
  U11(X1, active(X2), X3) -> U11(X1, X2, X3)
  U11(X1, X2, active(X3)) -> U11(X1, X2, X3)
  U12(mark(X1), X2, X3) -> U12(X1, X2, X3)
  U12(X1, mark(X2), X3) -> U12(X1, X2, X3)
  U12(X1, X2, mark(X3)) -> U12(X1, X2, X3)
  U12(active(X1), X2, X3) -> U12(X1, X2, X3)
  U12(X1, active(X2), X3) -> U12(X1, X2, X3)
  U12(X1, X2, active(X3)) -> U12(X1, X2, X3)
  active(U11(tt, M, N)) -> mark(U12(tt, M, N))
  active(U12(tt, M, N)) -> mark(s(plus(N, M)))
  active(plus(N, 0)) -> mark(N)
  active(plus(N, s(M))) -> mark(U11(tt, M, N))
  mark(U11(X1, X2, X3)) -> active(U11(mark(X1), X2, X3))
  mark(tt) -> active(tt)
  mark(U12(X1, X2, X3)) -> active(U12(mark(X1), X2, X3))
  mark(s(X)) -> active(s(mark(X)))
  mark(plus(X1, X2)) -> active(plus(mark(X1), mark(X2)))
  mark(0) -> active(0)
  plus(mark(X1), X2) -> plus(X1, X2)
  plus(X1, mark(X2)) -> plus(X1, X2)
  plus(active(X1), X2) -> plus(X1, X2)
  plus(X1, active(X2)) -> plus(X1, X2)
  s(mark(X)) -> s(X)
  s(active(X)) -> s(X)
  
   the pairs 
  plus#(active(X1), X2) -> plus#(X1, X2)
  
  could not apply the generic root reduction pair processor with the following
  SCNP-version with mu = MS and the level mapping defined by 
  pi(plus#) = [(epsilon,0),(1,1)]
  Argument Filter: 
  pi(plus#/2) = []
  pi(mark/1) = 1
  pi(active/1) = [1]
  
  RPO with the following precedence
  precedence(plus#[2]) = 0
  precedence(active[1]) = 1
  
  precedence(_) = 0
  and the following status
  status(plus#[2]) = lex
  status(active[1]) = lex
  
  status(_) = lex
  
  problem when orienting DPs
  cannot orient pair plus#(mark(X1), X2) -> plus#(X1, X2) weakly:
  [(plus#(mark(X1), X2),0),(mark(X1),1)] >=mu [(plus#(X1, X2),0),(X1,1)] could not be ensured