ceta_eq: termination proof not accepted 1: error below switch to dependency pairs 1.1: error below the dependency graph processor 1.1.1: error when applying the reduction pair processor with usable rules to remove from the DP problem pairs: sel#(s(X), cons(Y, Z)) -> sel#(X, activate(Z)) rules: activate(n__from(X)) -> from(activate(X)) activate(n__s(X)) -> s(activate(X)) activate(n__first(X1, X2)) -> first(activate(X1), activate(X2)) activate(X) -> X first(0, Z) -> nil first(s(X), cons(Y, Z)) -> cons(Y, n__first(X, activate(Z))) first(X1, X2) -> n__first(X1, X2) from(X) -> cons(X, n__from(n__s(X))) from(X) -> n__from(X) s(X) -> n__s(X) sel(0, cons(X, Z)) -> X sel(s(X), cons(Y, Z)) -> sel(X, activate(Z)) the pairs sel#(s(X), cons(Y, Z)) -> sel#(X, activate(Z)) could not apply the generic root reduction pair processor with the following SCNP-version with mu = MIN and the level mapping defined by pi(sel#) = [(epsilon,0),(1,1)] Argument Filter: pi(sel#/2) = [1,2] pi(s/1) = [1] pi(cons/2) = [] pi(activate/1) = [1] pi(n__from/1) = [1] pi(from/1) = [1] pi(n__s/1) = [1] pi(n__first/2) = [1,2] pi(first/2) = [1,2] pi(0/0) = [] pi(nil/0) = [] RPO with the following precedence precedence(sel#[2]) = 3 precedence(s[1]) = 3 precedence(cons[2]) = 3 precedence(activate[1]) = 3 precedence(n__from[1]) = 3 precedence(from[1]) = 3 precedence(n__s[1]) = 3 precedence(n__first[2]) = 0 precedence(first[2]) = 2 precedence(0[0]) = 4 precedence(nil[0]) = 1 precedence(_) = 0 and the following status status(sel#[2]) = mul status(s[1]) = mul status(cons[2]) = mul status(activate[1]) = mul status(n__from[1]) = mul status(from[1]) = mul status(n__s[1]) = mul status(n__first[2]) = mul status(first[2]) = mul status(0[0]) = mul status(nil[0]) = mul status(_) = lex problem when orienting (usable) rules could not orient activate(n__from(X)) >= from(activate(X)) pi( activate(n__from(X)) ) = activate(n__from(X)) pi( from(activate(X)) ) = from(activate(X)) could not orient activate(n__from(X)) >=RPO from(activate(X))