ceta_equiv: termination proof not accepted 1: error below switch to dependency pairs 1.1: error below the dependency graph processor 1.1.1: error below the reduction pair processor 1.1.1.1: error when applying the reduction pair processor with usable rules to remove from the DP problem pairs: ren#(X, Y, lambda(Z, T)) -> ren#(X, Y, ren(Z, var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), T)) ren#(X, Y, lambda(Z, T)) -> ren#(Z, var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), T) rules: and(false, false) -> false and(true, false) -> false and(false, true) -> false and(true, true) -> true eq(nil, nil) -> true eq(cons(T, L), nil) -> false eq(nil, cons(T, L)) -> false eq(cons(T, L), cons(Tp, Lp)) -> and(eq(T, Tp), eq(L, Lp)) eq(var(L), var(Lp)) -> eq(L, Lp) eq(var(L), apply(T, S)) -> false eq(var(L), lambda(X, T)) -> false eq(apply(T, S), var(L)) -> false eq(apply(T, S), apply(Tp, Sp)) -> and(eq(T, Tp), eq(S, Sp)) eq(apply(T, S), lambda(X, Tp)) -> false eq(lambda(X, T), var(L)) -> false eq(lambda(X, T), apply(Tp, Sp)) -> false eq(lambda(X, T), lambda(Xp, Tp)) -> and(eq(T, Tp), eq(X, Xp)) if(true, var(K), var(L)) -> var(K) if(false, var(K), var(L)) -> var(L) ren(var(L), var(K), var(Lp)) -> if(eq(L, Lp), var(K), var(Lp)) ren(X, Y, apply(T, S)) -> apply(ren(X, Y, T), ren(X, Y, S)) ren(X, Y, lambda(Z, T)) -> lambda(var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), ren(X, Y, ren(Z, var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), T))) the pairs ren#(X, Y, lambda(Z, T)) -> ren#(X, Y, ren(Z, var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), T)) ren#(X, Y, lambda(Z, T)) -> ren#(Z, var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), T) could not apply the generic reduction pair processor with the following Argument Filter: pi(ren#/3) = [1,2,3] pi(lambda/2) = [1,2] pi(ren/3) = 3 pi(var/1) = [] pi(cons/2) = [] pi(nil/0) = [] pi(if/3) = 2 pi(eq/2) = [1] pi(apply/2) = 2 pi(true/0) = [] pi(false/0) = [] pi(and/2) = [2,1] RPO with the following precedence precedence(ren#[3]) = 4 precedence(lambda[2]) = 3 precedence(var[1]) = 0 precedence(cons[2]) = 2 precedence(nil[0]) = 0 precedence(eq[2]) = 1 precedence(true[0]) = 0 precedence(false[0]) = 5 precedence(and[2]) = 6 precedence(_) = 0 and the following status status(ren#[3]) = mul status(lambda[2]) = mul status(var[1]) = mul status(cons[2]) = lex status(nil[0]) = mul status(eq[2]) = lex status(true[0]) = mul status(false[0]) = mul status(and[2]) = lex status(_) = lex problem when orienting (usable) rules could not orient ren(X, Y, lambda(Z, T)) >= lambda(var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), ren(X, Y, ren(Z, var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), T))) pi( ren(X, Y, lambda(Z, T)) ) = lambda(Z, T) pi( lambda(var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), ren(X, Y, ren(Z, var(cons(X, cons(Y, cons(lambda(Z, T), nil)))), T))) ) = lambda(var, T) could not orient lambda(Z, T) >=RPO lambda(var, T)