3.73/1.78 YES 3.73/1.79 proof of /export/starexec/sandbox/benchmark/theBenchmark.pl 3.73/1.79 # AProVE Commit ID: 48fb2092695e11cc9f56e44b17a92a5f88ffb256 marcel 20180622 unpublished dirty 3.73/1.79 3.73/1.79 3.73/1.79 Left Termination of the query pattern 3.73/1.79 3.73/1.79 palindrome(g) 3.73/1.79 3.73/1.79 w.r.t. the given Prolog program could successfully be proven: 3.73/1.79 3.73/1.79 (0) Prolog 3.73/1.79 (1) PrologToPiTRSProof [SOUND, 0 ms] 3.73/1.79 (2) PiTRS 3.73/1.79 (3) DependencyPairsProof [EQUIVALENT, 0 ms] 3.73/1.79 (4) PiDP 3.73/1.79 (5) DependencyGraphProof [EQUIVALENT, 0 ms] 3.73/1.79 (6) PiDP 3.73/1.79 (7) UsableRulesProof [EQUIVALENT, 0 ms] 3.73/1.79 (8) PiDP 3.73/1.79 (9) PiDPToQDPProof [EQUIVALENT, 0 ms] 3.73/1.79 (10) QDP 3.73/1.79 (11) QDPSizeChangeProof [EQUIVALENT, 0 ms] 3.73/1.79 (12) YES 3.73/1.79 3.73/1.79 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (0) 3.73/1.79 Obligation: 3.73/1.79 Clauses: 3.73/1.79 3.73/1.79 palindrome(Xs) :- reverse(Xs, Xs). 3.73/1.79 reverse(X1s, X2s) :- reverse3(X1s, [], X2s). 3.73/1.79 reverse3(.(X, X1s), X2s, Ys) :- reverse3(X1s, .(X, X2s), Ys). 3.73/1.79 reverse3([], Xs, Xs). 3.73/1.79 3.73/1.79 3.73/1.79 Query: palindrome(g) 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (1) PrologToPiTRSProof (SOUND) 3.73/1.79 We use the technique of [TOCL09]. With regard to the inferred argument filtering the predicates were used in the following modes: 3.73/1.79 3.73/1.79 palindrome_in_1: (b) 3.73/1.79 3.73/1.79 reverse_in_2: (b,b) 3.73/1.79 3.73/1.79 reverse3_in_3: (b,b,b) 3.73/1.79 3.73/1.79 Transforming Prolog into the following Term Rewriting System: 3.73/1.79 3.73/1.79 Pi-finite rewrite system: 3.73/1.79 The TRS R consists of the following rules: 3.73/1.79 3.73/1.79 palindrome_in_g(Xs) -> U1_g(Xs, reverse_in_gg(Xs, Xs)) 3.73/1.79 reverse_in_gg(X1s, X2s) -> U2_gg(X1s, X2s, reverse3_in_ggg(X1s, [], X2s)) 3.73/1.79 reverse3_in_ggg(.(X, X1s), X2s, Ys) -> U3_ggg(X, X1s, X2s, Ys, reverse3_in_ggg(X1s, .(X, X2s), Ys)) 3.73/1.79 reverse3_in_ggg([], Xs, Xs) -> reverse3_out_ggg([], Xs, Xs) 3.73/1.79 U3_ggg(X, X1s, X2s, Ys, reverse3_out_ggg(X1s, .(X, X2s), Ys)) -> reverse3_out_ggg(.(X, X1s), X2s, Ys) 3.73/1.79 U2_gg(X1s, X2s, reverse3_out_ggg(X1s, [], X2s)) -> reverse_out_gg(X1s, X2s) 3.73/1.79 U1_g(Xs, reverse_out_gg(Xs, Xs)) -> palindrome_out_g(Xs) 3.73/1.79 3.73/1.79 The argument filtering Pi contains the following mapping: 3.73/1.79 palindrome_in_g(x1) = palindrome_in_g(x1) 3.73/1.79 3.73/1.79 U1_g(x1, x2) = U1_g(x2) 3.73/1.79 3.73/1.79 reverse_in_gg(x1, x2) = reverse_in_gg(x1, x2) 3.73/1.79 3.73/1.79 U2_gg(x1, x2, x3) = U2_gg(x3) 3.73/1.79 3.73/1.79 reverse3_in_ggg(x1, x2, x3) = reverse3_in_ggg(x1, x2, x3) 3.73/1.79 3.73/1.79 .(x1, x2) = .(x1, x2) 3.73/1.79 3.73/1.79 U3_ggg(x1, x2, x3, x4, x5) = U3_ggg(x5) 3.73/1.79 3.73/1.79 [] = [] 3.73/1.79 3.73/1.79 reverse3_out_ggg(x1, x2, x3) = reverse3_out_ggg 3.73/1.79 3.73/1.79 reverse_out_gg(x1, x2) = reverse_out_gg 3.73/1.79 3.73/1.79 palindrome_out_g(x1) = palindrome_out_g 3.73/1.79 3.73/1.79 3.73/1.79 3.73/1.79 3.73/1.79 3.73/1.79 Infinitary Constructor Rewriting Termination of PiTRS implies Termination of Prolog 3.73/1.79 3.73/1.79 3.73/1.79 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (2) 3.73/1.79 Obligation: 3.73/1.79 Pi-finite rewrite system: 3.73/1.79 The TRS R consists of the following rules: 3.73/1.79 3.73/1.79 palindrome_in_g(Xs) -> U1_g(Xs, reverse_in_gg(Xs, Xs)) 3.73/1.79 reverse_in_gg(X1s, X2s) -> U2_gg(X1s, X2s, reverse3_in_ggg(X1s, [], X2s)) 3.73/1.79 reverse3_in_ggg(.(X, X1s), X2s, Ys) -> U3_ggg(X, X1s, X2s, Ys, reverse3_in_ggg(X1s, .(X, X2s), Ys)) 3.73/1.79 reverse3_in_ggg([], Xs, Xs) -> reverse3_out_ggg([], Xs, Xs) 3.73/1.79 U3_ggg(X, X1s, X2s, Ys, reverse3_out_ggg(X1s, .(X, X2s), Ys)) -> reverse3_out_ggg(.(X, X1s), X2s, Ys) 3.73/1.79 U2_gg(X1s, X2s, reverse3_out_ggg(X1s, [], X2s)) -> reverse_out_gg(X1s, X2s) 3.73/1.79 U1_g(Xs, reverse_out_gg(Xs, Xs)) -> palindrome_out_g(Xs) 3.73/1.79 3.73/1.79 The argument filtering Pi contains the following mapping: 3.73/1.79 palindrome_in_g(x1) = palindrome_in_g(x1) 3.73/1.79 3.73/1.79 U1_g(x1, x2) = U1_g(x2) 3.73/1.79 3.73/1.79 reverse_in_gg(x1, x2) = reverse_in_gg(x1, x2) 3.73/1.79 3.73/1.79 U2_gg(x1, x2, x3) = U2_gg(x3) 3.73/1.79 3.73/1.79 reverse3_in_ggg(x1, x2, x3) = reverse3_in_ggg(x1, x2, x3) 3.73/1.79 3.73/1.79 .(x1, x2) = .(x1, x2) 3.73/1.79 3.73/1.79 U3_ggg(x1, x2, x3, x4, x5) = U3_ggg(x5) 3.73/1.79 3.73/1.79 [] = [] 3.73/1.79 3.73/1.79 reverse3_out_ggg(x1, x2, x3) = reverse3_out_ggg 3.73/1.79 3.73/1.79 reverse_out_gg(x1, x2) = reverse_out_gg 3.73/1.79 3.73/1.79 palindrome_out_g(x1) = palindrome_out_g 3.73/1.79 3.73/1.79 3.73/1.79 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (3) DependencyPairsProof (EQUIVALENT) 3.73/1.79 Using Dependency Pairs [AG00,LOPSTR] we result in the following initial DP problem: 3.73/1.79 Pi DP problem: 3.73/1.79 The TRS P consists of the following rules: 3.73/1.79 3.73/1.79 PALINDROME_IN_G(Xs) -> U1_G(Xs, reverse_in_gg(Xs, Xs)) 3.73/1.79 PALINDROME_IN_G(Xs) -> REVERSE_IN_GG(Xs, Xs) 3.73/1.79 REVERSE_IN_GG(X1s, X2s) -> U2_GG(X1s, X2s, reverse3_in_ggg(X1s, [], X2s)) 3.73/1.79 REVERSE_IN_GG(X1s, X2s) -> REVERSE3_IN_GGG(X1s, [], X2s) 3.73/1.79 REVERSE3_IN_GGG(.(X, X1s), X2s, Ys) -> U3_GGG(X, X1s, X2s, Ys, reverse3_in_ggg(X1s, .(X, X2s), Ys)) 3.73/1.79 REVERSE3_IN_GGG(.(X, X1s), X2s, Ys) -> REVERSE3_IN_GGG(X1s, .(X, X2s), Ys) 3.73/1.79 3.73/1.79 The TRS R consists of the following rules: 3.73/1.79 3.73/1.79 palindrome_in_g(Xs) -> U1_g(Xs, reverse_in_gg(Xs, Xs)) 3.73/1.79 reverse_in_gg(X1s, X2s) -> U2_gg(X1s, X2s, reverse3_in_ggg(X1s, [], X2s)) 3.73/1.79 reverse3_in_ggg(.(X, X1s), X2s, Ys) -> U3_ggg(X, X1s, X2s, Ys, reverse3_in_ggg(X1s, .(X, X2s), Ys)) 3.73/1.79 reverse3_in_ggg([], Xs, Xs) -> reverse3_out_ggg([], Xs, Xs) 3.73/1.79 U3_ggg(X, X1s, X2s, Ys, reverse3_out_ggg(X1s, .(X, X2s), Ys)) -> reverse3_out_ggg(.(X, X1s), X2s, Ys) 3.73/1.79 U2_gg(X1s, X2s, reverse3_out_ggg(X1s, [], X2s)) -> reverse_out_gg(X1s, X2s) 3.73/1.79 U1_g(Xs, reverse_out_gg(Xs, Xs)) -> palindrome_out_g(Xs) 3.73/1.79 3.73/1.79 The argument filtering Pi contains the following mapping: 3.73/1.79 palindrome_in_g(x1) = palindrome_in_g(x1) 3.73/1.79 3.73/1.79 U1_g(x1, x2) = U1_g(x2) 3.73/1.79 3.73/1.79 reverse_in_gg(x1, x2) = reverse_in_gg(x1, x2) 3.73/1.79 3.73/1.79 U2_gg(x1, x2, x3) = U2_gg(x3) 3.73/1.79 3.73/1.79 reverse3_in_ggg(x1, x2, x3) = reverse3_in_ggg(x1, x2, x3) 3.73/1.79 3.73/1.79 .(x1, x2) = .(x1, x2) 3.73/1.79 3.73/1.79 U3_ggg(x1, x2, x3, x4, x5) = U3_ggg(x5) 3.73/1.79 3.73/1.79 [] = [] 3.73/1.79 3.73/1.79 reverse3_out_ggg(x1, x2, x3) = reverse3_out_ggg 3.73/1.79 3.73/1.79 reverse_out_gg(x1, x2) = reverse_out_gg 3.73/1.79 3.73/1.79 palindrome_out_g(x1) = palindrome_out_g 3.73/1.79 3.73/1.79 PALINDROME_IN_G(x1) = PALINDROME_IN_G(x1) 3.73/1.79 3.73/1.79 U1_G(x1, x2) = U1_G(x2) 3.73/1.79 3.73/1.79 REVERSE_IN_GG(x1, x2) = REVERSE_IN_GG(x1, x2) 3.73/1.79 3.73/1.79 U2_GG(x1, x2, x3) = U2_GG(x3) 3.73/1.79 3.73/1.79 REVERSE3_IN_GGG(x1, x2, x3) = REVERSE3_IN_GGG(x1, x2, x3) 3.73/1.79 3.73/1.79 U3_GGG(x1, x2, x3, x4, x5) = U3_GGG(x5) 3.73/1.79 3.73/1.79 3.73/1.79 We have to consider all (P,R,Pi)-chains 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (4) 3.73/1.79 Obligation: 3.73/1.79 Pi DP problem: 3.73/1.79 The TRS P consists of the following rules: 3.73/1.79 3.73/1.79 PALINDROME_IN_G(Xs) -> U1_G(Xs, reverse_in_gg(Xs, Xs)) 3.73/1.79 PALINDROME_IN_G(Xs) -> REVERSE_IN_GG(Xs, Xs) 3.73/1.79 REVERSE_IN_GG(X1s, X2s) -> U2_GG(X1s, X2s, reverse3_in_ggg(X1s, [], X2s)) 3.73/1.79 REVERSE_IN_GG(X1s, X2s) -> REVERSE3_IN_GGG(X1s, [], X2s) 3.73/1.79 REVERSE3_IN_GGG(.(X, X1s), X2s, Ys) -> U3_GGG(X, X1s, X2s, Ys, reverse3_in_ggg(X1s, .(X, X2s), Ys)) 3.73/1.79 REVERSE3_IN_GGG(.(X, X1s), X2s, Ys) -> REVERSE3_IN_GGG(X1s, .(X, X2s), Ys) 3.73/1.79 3.73/1.79 The TRS R consists of the following rules: 3.73/1.79 3.73/1.79 palindrome_in_g(Xs) -> U1_g(Xs, reverse_in_gg(Xs, Xs)) 3.73/1.79 reverse_in_gg(X1s, X2s) -> U2_gg(X1s, X2s, reverse3_in_ggg(X1s, [], X2s)) 3.73/1.79 reverse3_in_ggg(.(X, X1s), X2s, Ys) -> U3_ggg(X, X1s, X2s, Ys, reverse3_in_ggg(X1s, .(X, X2s), Ys)) 3.73/1.79 reverse3_in_ggg([], Xs, Xs) -> reverse3_out_ggg([], Xs, Xs) 3.73/1.79 U3_ggg(X, X1s, X2s, Ys, reverse3_out_ggg(X1s, .(X, X2s), Ys)) -> reverse3_out_ggg(.(X, X1s), X2s, Ys) 3.73/1.79 U2_gg(X1s, X2s, reverse3_out_ggg(X1s, [], X2s)) -> reverse_out_gg(X1s, X2s) 3.73/1.79 U1_g(Xs, reverse_out_gg(Xs, Xs)) -> palindrome_out_g(Xs) 3.73/1.79 3.73/1.79 The argument filtering Pi contains the following mapping: 3.73/1.79 palindrome_in_g(x1) = palindrome_in_g(x1) 3.73/1.79 3.73/1.79 U1_g(x1, x2) = U1_g(x2) 3.73/1.79 3.73/1.79 reverse_in_gg(x1, x2) = reverse_in_gg(x1, x2) 3.73/1.79 3.73/1.79 U2_gg(x1, x2, x3) = U2_gg(x3) 3.73/1.79 3.73/1.79 reverse3_in_ggg(x1, x2, x3) = reverse3_in_ggg(x1, x2, x3) 3.73/1.79 3.73/1.79 .(x1, x2) = .(x1, x2) 3.73/1.79 3.73/1.79 U3_ggg(x1, x2, x3, x4, x5) = U3_ggg(x5) 3.73/1.79 3.73/1.79 [] = [] 3.73/1.79 3.73/1.79 reverse3_out_ggg(x1, x2, x3) = reverse3_out_ggg 3.73/1.79 3.73/1.79 reverse_out_gg(x1, x2) = reverse_out_gg 3.73/1.79 3.73/1.79 palindrome_out_g(x1) = palindrome_out_g 3.73/1.79 3.73/1.79 PALINDROME_IN_G(x1) = PALINDROME_IN_G(x1) 3.73/1.79 3.73/1.79 U1_G(x1, x2) = U1_G(x2) 3.73/1.79 3.73/1.79 REVERSE_IN_GG(x1, x2) = REVERSE_IN_GG(x1, x2) 3.73/1.79 3.73/1.79 U2_GG(x1, x2, x3) = U2_GG(x3) 3.73/1.79 3.73/1.79 REVERSE3_IN_GGG(x1, x2, x3) = REVERSE3_IN_GGG(x1, x2, x3) 3.73/1.79 3.73/1.79 U3_GGG(x1, x2, x3, x4, x5) = U3_GGG(x5) 3.73/1.79 3.73/1.79 3.73/1.79 We have to consider all (P,R,Pi)-chains 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (5) DependencyGraphProof (EQUIVALENT) 3.73/1.79 The approximation of the Dependency Graph [LOPSTR] contains 1 SCC with 5 less nodes. 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (6) 3.73/1.79 Obligation: 3.73/1.79 Pi DP problem: 3.73/1.79 The TRS P consists of the following rules: 3.73/1.79 3.73/1.79 REVERSE3_IN_GGG(.(X, X1s), X2s, Ys) -> REVERSE3_IN_GGG(X1s, .(X, X2s), Ys) 3.73/1.79 3.73/1.79 The TRS R consists of the following rules: 3.73/1.79 3.73/1.79 palindrome_in_g(Xs) -> U1_g(Xs, reverse_in_gg(Xs, Xs)) 3.73/1.79 reverse_in_gg(X1s, X2s) -> U2_gg(X1s, X2s, reverse3_in_ggg(X1s, [], X2s)) 3.73/1.79 reverse3_in_ggg(.(X, X1s), X2s, Ys) -> U3_ggg(X, X1s, X2s, Ys, reverse3_in_ggg(X1s, .(X, X2s), Ys)) 3.73/1.79 reverse3_in_ggg([], Xs, Xs) -> reverse3_out_ggg([], Xs, Xs) 3.73/1.79 U3_ggg(X, X1s, X2s, Ys, reverse3_out_ggg(X1s, .(X, X2s), Ys)) -> reverse3_out_ggg(.(X, X1s), X2s, Ys) 3.73/1.79 U2_gg(X1s, X2s, reverse3_out_ggg(X1s, [], X2s)) -> reverse_out_gg(X1s, X2s) 3.73/1.79 U1_g(Xs, reverse_out_gg(Xs, Xs)) -> palindrome_out_g(Xs) 3.73/1.79 3.73/1.79 The argument filtering Pi contains the following mapping: 3.73/1.79 palindrome_in_g(x1) = palindrome_in_g(x1) 3.73/1.79 3.73/1.79 U1_g(x1, x2) = U1_g(x2) 3.73/1.79 3.73/1.79 reverse_in_gg(x1, x2) = reverse_in_gg(x1, x2) 3.73/1.79 3.73/1.79 U2_gg(x1, x2, x3) = U2_gg(x3) 3.73/1.79 3.73/1.79 reverse3_in_ggg(x1, x2, x3) = reverse3_in_ggg(x1, x2, x3) 3.73/1.79 3.73/1.79 .(x1, x2) = .(x1, x2) 3.73/1.79 3.73/1.79 U3_ggg(x1, x2, x3, x4, x5) = U3_ggg(x5) 3.73/1.79 3.73/1.79 [] = [] 3.73/1.79 3.73/1.79 reverse3_out_ggg(x1, x2, x3) = reverse3_out_ggg 3.73/1.79 3.73/1.79 reverse_out_gg(x1, x2) = reverse_out_gg 3.73/1.79 3.73/1.79 palindrome_out_g(x1) = palindrome_out_g 3.73/1.79 3.73/1.79 REVERSE3_IN_GGG(x1, x2, x3) = REVERSE3_IN_GGG(x1, x2, x3) 3.73/1.79 3.73/1.79 3.73/1.79 We have to consider all (P,R,Pi)-chains 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (7) UsableRulesProof (EQUIVALENT) 3.73/1.79 For (infinitary) constructor rewriting [LOPSTR] we can delete all non-usable rules from R. 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (8) 3.73/1.79 Obligation: 3.73/1.79 Pi DP problem: 3.73/1.79 The TRS P consists of the following rules: 3.73/1.79 3.73/1.79 REVERSE3_IN_GGG(.(X, X1s), X2s, Ys) -> REVERSE3_IN_GGG(X1s, .(X, X2s), Ys) 3.73/1.79 3.73/1.79 R is empty. 3.73/1.79 Pi is empty. 3.73/1.79 We have to consider all (P,R,Pi)-chains 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (9) PiDPToQDPProof (EQUIVALENT) 3.73/1.79 Transforming (infinitary) constructor rewriting Pi-DP problem [LOPSTR] into ordinary QDP problem [LPAR04] by application of Pi. 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (10) 3.73/1.79 Obligation: 3.73/1.79 Q DP problem: 3.73/1.79 The TRS P consists of the following rules: 3.73/1.79 3.73/1.79 REVERSE3_IN_GGG(.(X, X1s), X2s, Ys) -> REVERSE3_IN_GGG(X1s, .(X, X2s), Ys) 3.73/1.79 3.73/1.79 R is empty. 3.73/1.79 Q is empty. 3.73/1.79 We have to consider all (P,Q,R)-chains. 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (11) QDPSizeChangeProof (EQUIVALENT) 3.73/1.79 By using the subterm criterion [SUBTERM_CRITERION] together with the size-change analysis [AAECC05] we have proven that there are no infinite chains for this DP problem. 3.73/1.79 3.73/1.79 From the DPs we obtained the following set of size-change graphs: 3.73/1.79 *REVERSE3_IN_GGG(.(X, X1s), X2s, Ys) -> REVERSE3_IN_GGG(X1s, .(X, X2s), Ys) 3.73/1.79 The graph contains the following edges 1 > 1, 3 >= 3 3.73/1.79 3.73/1.79 3.73/1.79 ---------------------------------------- 3.73/1.79 3.73/1.79 (12) 3.73/1.79 YES 4.07/1.83 EOF