MAYBE (ignored inputs)COMMENT Queue. Rewrite Rules: [ q(e,?x) -> ?x, q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(?x,?y) -> eq(?y,?x) ] Apply Direct Methods... Inner CPs: [ q(?x,?z_1) = q(e,q(?x,?z_1)), q(q(q(?x_2,?y_2),?z_2),?z_1) = q(?x_2,q(q(?y_2,?z_2),?z_1)), q(?x_2,?x) = q(q(?x_2,e),?x), q(?x_2,q(?x_1,q(?y_1,?z_1))) = q(q(?x_2,q(?x_1,?y_1)),?z_1), eq(e,q(q(a,?y_2),?z_2)) = false, eq(q(q(a,?y_2),?z_2),q(a,?y_4)) = eq(q(?y_2,?z_2),?y_4), eq(q(a,?x_4),q(q(a,?y_2),?z_2)) = eq(?x_4,q(?y_2,?z_2)), q(q(?x,q(?y,?z)),?z_1) = q(q(?x,?y),q(?z,?z_1)), q(?x_1,q(q(?x,?y),?z)) = q(q(?x_1,?x),q(?y,?z)) ] Outer CPs: [ q(?y_2,?z_2) = q(q(e,?y_2),?z_2), q(?x_1,q(?y_1,q(?y_2,?z_2))) = q(q(q(?x_1,?y_1),?y_2),?z_2), false = eq(q(a,?x_3),e), eq(?x_4,?y_4) = eq(q(a,?y_4),q(a,?x_4)) ] not Overlay, check Termination... unknown/not Terminating unknown Knuth & Bendix Linear unknown Development Closed unknown Strongly Closed unknown Weakly-Non-Overlapping & Non-Collapsing & Shallow unknown Upside-Parallel-Closed/Outside-Closed (inner) Parallel CPs: (not computed) unknown Toyama (Parallel CPs) Simultaneous CPs: [ q(q(e,?y_2),?z_2) = q(?y_2,?z_2), q(e,q(?x,?z_2)) = q(?x,?z_2), q(q(?x_3,e),?x) = q(?x_3,?x), q(q(q(?x_3,q(?y_3,?y)),?y_2),?z_2) = q(q(?x_3,?y_3),q(?y,q(?y_2,?z_2))), q(q(?y,?y_2),?z_2) = q(e,q(?y,q(?y_2,?z_2))), q(q(q(q(?x,?y_5),?z_5),?y_2),?z_2) = q(?x,q(q(?y_5,?z_5),q(?y_2,?z_2))), q(q(q(?x,?y),?y_2),?z_2) = q(?x,q(?y,q(?y_2,?z_2))), q(q(?x_1,q(?y_1,?y)),?z) = q(q(?x_1,?y_1),q(?y,?z)), q(?y,?z) = q(e,q(?y,?z)), q(q(q(?x,?y_3),?z_3),?z) = q(?x,q(q(?y_3,?z_3),?z)), q(q(?x_2,q(?y_2,?y)),q(?z,?z_1)) = q(q(q(?x_2,?y_2),q(?y,?z)),?z_1), q(?y,q(?z,?z_1)) = q(q(e,q(?y,?z)),?z_1), q(q(q(?x,?y_4),?z_4),q(?z,?z_1)) = q(q(?x,q(q(?y_4,?z_4),?z)),?z_1), q(q(?x_3,q(?x_4,q(?y_4,?y))),?z) = q(?x_3,q(q(?x_4,?y_4),q(?y,?z))), q(q(?x_3,?y),?z) = q(?x_3,q(e,q(?y,?z))), q(q(?x_3,q(q(?x,?y_6),?z_6)),?z) = q(?x_3,q(?x,q(q(?y_6,?z_6),?z))), q(q(?x,?y),q(?z,?z_1)) = q(q(?x,q(?y,?z)),?z_1), q(q(?x_3,q(?x,?y)),?z) = q(?x_3,q(?x,q(?y,?z))), q(q(?y,?y_1),?z_1) = q(q(e,?y),q(?y_1,?z_1)), ?z = q(q(e,e),?z), q(?x_2,q(?y_2,q(q(?y,?y_3),?z_3))) = q(q(q(?x_2,?y_2),?y),q(?y_3,?z_3)), q(?x_2,q(?y_2,?z)) = q(q(q(?x_2,?y_2),e),?z), q(?x_2,q(?y_2,q(?x_5,q(?y_5,?z)))) = q(q(q(?x_2,?y_2),q(?x_5,?y_5)),?z), q(?y,?z) = q(q(e,?y),?z), q(?x_2,q(?y_2,q(?y,?z))) = q(q(q(?x_2,?y_2),?y),?z), q(?x,q(q(?y,?y_1),?z_1)) = q(q(?x,?y),q(?y_1,?z_1)), q(?x,?z) = q(q(?x,e),?z), q(?x,q(?x_3,q(?y_3,?z))) = q(q(?x,q(?x_3,?y_3)),?z), q(q(?x_1,?x),q(q(?y,?y_2),?z_2)) = q(?x_1,q(q(?x,?y),q(?y_2,?z_2))), q(q(?x_1,?x),?z) = q(?x_1,q(q(?x,e),?z)), q(q(?x_1,?x),q(?x_4,q(?y_4,?z))) = q(?x_1,q(q(?x,q(?x_4,?y_4)),?z)), q(?x,q(q(q(?y,?y_4),?z_4),?z_3)) = q(q(q(?x,?y),q(?y_4,?z_4)),?z_3), q(?x,q(?z,?z_3)) = q(q(q(?x,e),?z),?z_3), q(?x,q(q(?x_6,q(?y_6,?z)),?z_3)) = q(q(q(?x,q(?x_6,?y_6)),?z),?z_3), false = eq(e,q(q(a,?y),q(?y_1,?z_1))), false = eq(e,q(q(a,e),?z)), false = eq(e,q(q(a,q(?x_3,?y_3)),?z)), eq(q(q(?y,?y_6),?z_6),?y_5) = eq(q(q(a,?y),q(?y_6,?z_6)),q(a,?y_5)), eq(?z,?y_5) = eq(q(q(a,e),?z),q(a,?y_5)), eq(q(?x_8,q(?y_8,?z)),?y_5) = eq(q(q(a,q(?x_8,?y_8)),?z),q(a,?y_5)), eq(?x_5,q(q(?y,?y_6),?z_6)) = eq(q(a,?x_5),q(q(a,?y),q(?y_6,?z_6))), eq(?x_5,?z) = eq(q(a,?x_5),q(q(a,e),?z)), eq(?x_5,q(?x_8,q(?y_8,?z))) = eq(q(a,?x_5),q(q(a,q(?x_8,?y_8)),?z)), q(q(?x_1,?x),q(?y,?z)) = q(?x_1,q(q(?x,?y),?z)), q(?x,q(q(?y,?z),?z_3)) = q(q(q(?x,?y),?z),?z_3), false = eq(e,q(q(a,?y),?z)), eq(q(?y,?z),?y_5) = eq(q(q(a,?y),?z),q(a,?y_5)), eq(?x_5,q(?y,?z)) = eq(q(a,?x_5),q(q(a,?y),?z)), eq(q(q(a,?y_4),?z_4),e) = false, eq(q(a,?x),e) = false, eq(e,q(q(a,?y_4),?z_4)) = false, eq(q(q(a,?y_8),?z_8),q(q(a,?y_4),?z_4)) = eq(q(?y_4,?z_4),q(?y_8,?z_8)), eq(q(a,?y),q(q(a,?y_4),?z_4)) = eq(q(?y_4,?z_4),?y), eq(q(q(a,?y_4),?z_4),q(a,?x)) = eq(?x,q(?y_4,?z_4)), eq(q(q(a,?y_4),?z_4),q(q(a,?y_8),?z_8)) = eq(q(?y_4,?z_4),q(?y_8,?z_8)), eq(q(a,?y),q(a,?x)) = eq(?x,?y), eq(q(q(a,?y_4),?z_4),q(a,?y)) = eq(q(?y_4,?z_4),?y), eq(q(a,?x),q(q(a,?y_4),?z_4)) = eq(?x,q(?y_4,?z_4)), false = eq(q(a,?x_4),e), eq(?x_5,?y_5) = eq(q(a,?y_5),q(a,?x_5)) ] unknown Okui (Simultaneous CPs) unknown Strongly Depth-Preserving & Root-E-Closed/Non-E-Overlapping unknown Strongly Weight-Preserving & Root-E-Closed/Non-E-Overlapping check Locally Decreasing Diagrams by Rule Labelling... Critical Pair by Rules <0, 1> preceded by [(q,1)] joinable by a reduction of rules <[], [([],0)]> Critical Pair by Rules <2, 1> preceded by [(q,1)] joinable by a reduction of rules <[([(q,1)],1)], [([],2)]> Critical Pair by Rules <0, 2> preceded by [(q,2)] joinable by a reduction of rules <[], [([],1),([(q,2)],0)]> Critical Pair by Rules <1, 2> preceded by [(q,2)] joinable by a reduction of rules <[([(q,2)],2)], [([],1)]> Critical Pair by Rules <2, 3> preceded by [(eq,2)] joinable by a reduction of rules <[([(eq,2)],1),([],3)], []> Critical Pair by Rules <2, 4> preceded by [(eq,1)] joinable by a reduction of rules <[([(eq,1)],1),([],4)], []> Critical Pair by Rules <2, 4> preceded by [(eq,2)] joinable by a reduction of rules <[([(eq,2)],1),([],4)], []> Critical Pair by Rules <1, 1> preceded by [(q,1)] joinable by a reduction of rules <[([(q,1)],2)], [([],2)]> Critical Pair by Rules <2, 2> preceded by [(q,2)] joinable by a reduction of rules <[([(q,2)],1)], [([],1)]> Critical Pair by Rules <2, 0> preceded by [] joinable by a reduction of rules <[([(q,1)],0)], []> Critical Pair by Rules <2, 1> preceded by [] joinable by a reduction of rules <[([],1)], [([],2)]> Critical Pair by Rules <5, 3> preceded by [] joinable by a reduction of rules <[([],5),([],3)], []> Critical Pair by Rules <5, 4> preceded by [] joinable by a reduction of rules <[([],4)], [([],5)]> unknown Diagram Decreasing check Non-Confluence... obtain 16 rules by 3 steps unfolding strenghten q(e,?x) and ?x strenghten eq(?x_8,?y_8) and eq(?y_8,?x_8) strenghten q(q(e,e),?x_11) and ?x_11 strenghten eq(e,q(a,?x_3)) and false strenghten eq(q(a,?x_3),e) and false strenghten q(e,q(?x,?z_1)) and q(?x,?z_1) strenghten q(q(?x_2,e),?x) and q(?x_2,?x) strenghten q(q(e,?y_2),?z_2) and q(?y_2,?z_2) strenghten eq(e,q(q(a,?y_2),?z_2)) and false strenghten q(e,q(q(e,?x_11),?z_1)) and q(?x_11,?z_1) strenghten q(q(?x_2,e),q(e,?x_11)) and q(?x_2,?x_11) strenghten eq(q(a,?x_4),q(a,?y_4)) and eq(?x_4,?y_4) strenghten eq(q(a,?y_4),q(a,?x_4)) and eq(?x_4,?y_4) strenghten q(?x_1,q(?y_1,q(?y_2,?z_2))) and q(q(q(?x_1,?y_1),?y_2),?z_2) strenghten q(?x_2,q(q(?y_2,?z_2),?z_1)) and q(q(q(?x_2,?y_2),?z_2),?z_1) strenghten q(q(?x,?y),q(?z,?z_1)) and q(q(?x,q(?y,?z)),?z_1) strenghten q(q(?x_1,?x),q(?y,?z)) and q(?x_1,q(q(?x,?y),?z)) strenghten q(q(?x_2,q(?x_1,?y_1)),?z_1) and q(?x_2,q(?x_1,q(?y_1,?z_1))) strenghten eq(q(a,?x_4),q(q(a,?y_2),?z_2)) and eq(?x_4,q(?y_2,?z_2)) strenghten eq(q(q(a,?y_2),?z_2),q(a,?y_4)) and eq(q(?y_2,?z_2),?y_4) obtain 56 candidates for checking non-joinability check by TCAP-Approximation (failure) check by Root-Approximation (failure) check by Ordering(rpo), check by Tree-Automata Approximation (failure) check by Interpretation(mod2) (failure) check by Descendants-Approximation, check by Ordering(poly) (failure) unknown Non-Confluence Check relative termination: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z) ] [ eq(?x,?y) -> eq(?y,?x) ] Polynomial Interpretation: a:= 0 e:= 0 q:= (1)*x1+(1)*x2 eq:= (9)+(8)*x1+(8)*x2 false:= 0 retract eq(e,q(a,?x)) -> false Polynomial Interpretation: a:= 0 e:= (12) q:= (1)*x1+(1)*x2 eq:= (8)+(8)*x1+(8)*x2 false:= 0 retract q(e,?x) -> ?x retract eq(e,q(a,?x)) -> false Polynomial Interpretation: a:= (4) e:= (8) q:= (1)*x1+(1)*x2 eq:= (2)+(1)*x1+(1)*x2 false:= 0 retract q(e,?x) -> ?x retract eq(e,q(a,?x)) -> false retract eq(q(a,?x),q(a,?y)) -> eq(?x,?y) retract q(e,?x) -> ?x retract eq(e,q(a,?x)) -> false retract eq(q(a,?x),q(a,?y)) -> eq(?x,?y) unknown relative termination unknown Huet (modulo AC) check by Reduction-Preserving Completion... STEP: 1 (parallel) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y) ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] S: terminating CP(S,S): PCP_in(symP,S): --> => no --> => no --> => no --> => no CP(S,symP): --> => yes --> => no --> => yes --> => no --> => yes check joinability condition: check modulo reachablity from false to eq(e,q(q(a,?y_1),?z_1)): maybe not reachable check modulo reachablity from eq(?x,q(?y_1,?z_1)) to eq(q(a,?x),q(q(a,?y_1),?z_1)): maybe not reachable check modulo reachablity from eq(q(?y_3,?z_3),?y) to eq(q(q(?x_3,?y_3),?z_3),q(a,?y)): maybe not reachable check modulo reachablity from eq(q(?y_3,?z_3),q(?y_1,?z_1)) to eq(q(q(?x_3,?y_3),?z_3),q(q(a,?y_1),?z_1)): maybe not reachable check modulo reachablity from q(?x_1,?x) to q(q(?x_1,e),?x): maybe not reachable check modulo reachablity from false to eq(q(a,?x),e): maybe not reachable failed failure(Step 1) [ eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false ] Added S-Rules: [ eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false ] Added P-Rules: [ ] STEP: 2 (linear) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y) ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] S: terminating CP(S,S): CP_in(symP,S): --> => no --> => no --> => no CP(S,symP): --> => yes --> => no --> => yes --> => no --> => yes check joinability condition: check modulo reachablity from false to eq(e,q(q(a,?y),?z)): maybe not reachable check modulo reachablity from eq(q(?y,?z),?y_1) to eq(q(q(a,?y),?z),q(a,?y_1)): maybe not reachable check modulo reachablity from eq(?x_1,q(?y,?z)) to eq(q(a,?x_1),q(q(a,?y),?z)): maybe not reachable check modulo reachablity from q(?x_1,?x) to q(q(?x_1,e),?x): maybe not reachable check modulo reachablity from false to eq(q(a,?x),e): maybe not reachable failed failure(Step 2) [ eq(e,q(q(a,?y),?z)) -> false, eq(q(a,?x),e) -> false ] Added S-Rules: [ eq(e,q(q(a,?y),?z)) -> false, eq(q(a,?x),e) -> false ] Added P-Rules: [ ] STEP: 3 (relative) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y) ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] Check relative termination: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y) ] [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] Polynomial Interpretation: a:= 0 e:= 0 q:= (1)*x1+(1)*x2 eq:= (4)+(4)*x1+(4)*x1*x1+(4)*x2+(4)*x2*x2 false:= 0 retract eq(e,q(a,?x)) -> false Polynomial Interpretation: a:= 0 e:= (8) q:= (1)*x1+(1)*x2 eq:= (1)+(13)*x1+(14)*x1*x1+(13)*x2+(14)*x2*x2 false:= 0 retract q(e,?x) -> ?x retract eq(e,q(a,?x)) -> false Polynomial Interpretation: a:= 0 e:= 0 q:= (2)+(2)*x1+(1)*x1*x2+(2)*x2 eq:= (5)+(4)*x1+(6)*x1*x1+(1)*x1*x2+(4)*x2+(6)*x2*x2 false:= 0 relatively terminating S/P: relatively terminating check CP condition: failed failure(Step 3) STEP: 4 (parallel) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] S: terminating CP(S,S): PCP_in(symP,S): --> => yes --> => no --> => no --> => no --> => no --> => yes --> => no --> => no CP(S,symP): --> => yes --> => no --> => yes --> => yes --> => yes --> => no --> => yes check joinability condition: check modulo reachablity from eq(?x,q(?y_1,?z_1)) to eq(q(a,?x),q(q(a,?y_1),?z_1)): maybe not reachable check modulo reachablity from eq(q(?y_3,?z_3),?y) to eq(q(q(?x_3,?y_3),?z_3),q(a,?y)): maybe not reachable check modulo reachablity from eq(q(?y_3,?z_3),q(?y_1,?z_1)) to eq(q(q(?x_3,?y_3),?z_3),q(q(a,?y_1),?z_1)): maybe not reachable check modulo reachablity from false to eq(e,q(q(q(?x_4,?y_4),?z_4),?z)): maybe not reachable check modulo reachablity from false to eq(e,q(q(q(a,?y),?y_1),?z_1)): maybe not reachable check modulo reachablity from false to eq(q(q(a,?y_1),?z_1),e): maybe not reachable check modulo reachablity from q(?x_1,?x) to q(q(?x_1,e),?x): maybe not reachable check modulo reachablity from false to eq(q(q(a,?y),?z),e): maybe not reachable failed failure(Step 4) [ eq(q(q(a,?y_1),?z_1),e) -> false ] Added S-Rules: [ eq(q(q(a,?y_1),?z_1),e) -> false ] Added P-Rules: [ ] STEP: 5 (linear) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] S: terminating CP(S,S): CP_in(symP,S): --> => yes --> => no --> => no --> => no --> => no --> => no --> => yes CP(S,symP): --> => yes --> => no --> => yes --> => yes --> => yes --> => no --> => yes check joinability condition: check modulo reachablity from eq(q(?y,?z),?y_1) to eq(q(q(a,?y),?z),q(a,?y_1)): maybe not reachable check modulo reachablity from eq(?x_1,q(?y,?z)) to eq(q(a,?x_1),q(q(a,?y),?z)): maybe not reachable check modulo reachablity from false to eq(e,q(q(q(a,?y_2),?y),?z)): maybe not reachable check modulo reachablity from false to eq(e,q(q(q(a,?y),?z),?z_2)): maybe not reachable check modulo reachablity from false to eq(q(q(a,?y),?z),e): maybe not reachable check modulo reachablity from q(?x_1,?x) to q(q(?x_1,e),?x): maybe not reachable check modulo reachablity from false to eq(q(q(a,?y),?z),e): maybe not reachable failed failure(Step 5) [ eq(q(q(a,?y),?z),e) -> false ] Added S-Rules: [ eq(q(q(a,?y),?z),e) -> false ] Added P-Rules: [ ] STEP: 6 (relative) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] Check relative termination: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false ] [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] Polynomial Interpretation: a:= 0 e:= (2) q:= (2)+(2)*x1+(1)*x1*x2+(2)*x2 eq:= (8)+(4)*x1+(2)*x1*x1+(4)*x2+(2)*x2*x2 false:= 0 retract q(e,?x) -> ?x retract eq(e,q(a,?x)) -> false retract eq(e,q(q(a,?y_1),?z_1)) -> false retract eq(q(a,?x),e) -> false Polynomial Interpretation: a:= (1) e:= 0 q:= (1)*x1+(1)*x2 eq:= (8)+(4)*x1+(2)*x1*x2+(4)*x2 false:= 0 relatively terminating S/P: relatively terminating check CP condition: failed failure(Step 6) STEP: 7 (parallel) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false, eq(q(q(a,?y_1),?z_1),e) -> false ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] S: terminating CP(S,S): PCP_in(symP,S): --> => yes --> => no --> => no --> => no --> => no --> => yes --> => no --> => yes --> => no --> => yes --> => no CP(S,symP): --> => yes --> => no --> => yes --> => yes --> => yes --> => yes --> => yes --> => yes check joinability condition: check modulo reachablity from eq(?x,q(?y_1,?z_1)) to eq(q(a,?x),q(q(a,?y_1),?z_1)): maybe not reachable check modulo reachablity from eq(q(?y_3,?z_3),?y) to eq(q(q(?x_3,?y_3),?z_3),q(a,?y)): maybe not reachable check modulo reachablity from eq(q(?y_3,?z_3),q(?y_1,?z_1)) to eq(q(q(?x_3,?y_3),?z_3),q(q(a,?y_1),?z_1)): maybe not reachable check modulo reachablity from false to eq(e,q(q(q(?x_4,?y_4),?z_4),?z)): maybe not reachable check modulo reachablity from false to eq(e,q(q(q(a,?y),?y_1),?z_1)): maybe not reachable check modulo reachablity from false to eq(q(q(q(?x_4,?y_4),?z_4),?z),e): maybe not reachable check modulo reachablity from false to eq(q(q(q(a,?y),?y_1),?z_1),e): maybe not reachable check modulo reachablity from q(?x_1,?x) to q(q(?x_1,e),?x): maybe not reachable failed failure(Step 7) [ ] Added S-Rules: [ ] Added P-Rules: [ ] STEP: 8 (linear) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false, eq(q(q(a,?y_1),?z_1),e) -> false ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] S: terminating CP(S,S): CP_in(symP,S): --> => yes --> => no --> => no --> => no --> => no --> => yes --> => no --> => no --> => yes --> => yes CP(S,symP): --> => yes --> => no --> => yes --> => yes --> => yes --> => yes --> => yes --> => yes check joinability condition: check modulo reachablity from eq(q(?y,?z),?y_1) to eq(q(q(a,?y),?z),q(a,?y_1)): maybe not reachable check modulo reachablity from eq(?x_1,q(?y,?z)) to eq(q(a,?x_1),q(q(a,?y),?z)): maybe not reachable check modulo reachablity from false to eq(e,q(q(q(a,?y_2),?y),?z)): maybe not reachable check modulo reachablity from false to eq(e,q(q(q(a,?y),?z),?z_2)): maybe not reachable check modulo reachablity from false to eq(q(q(q(a,?y_2),?y),?z),e): maybe not reachable check modulo reachablity from false to eq(q(q(q(a,?y),?z),?z_2),e): maybe not reachable check modulo reachablity from q(?x_1,?x) to q(q(?x_1,e),?x): maybe not reachable failed failure(Step 8) [ ] Added S-Rules: [ ] Added P-Rules: [ ] STEP: 9 (relative) S: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false, eq(q(q(a,?y_1),?z_1),e) -> false ] P: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] Check relative termination: [ q(e,?x) -> ?x, eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(q(a,?y_1),?z_1)) -> false, eq(q(a,?x),e) -> false, eq(q(q(a,?y_1),?z_1),e) -> false ] [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(?x,?y) -> eq(?y,?x) ] Polynomial Interpretation: a:= 0 e:= 0 q:= (1)*x1+(1)*x2 eq:= (8)+(8)*x1*x1+(8)*x2*x2 false:= 0 retract eq(e,q(a,?x)) -> false retract eq(e,q(q(a,?y_1),?z_1)) -> false retract eq(q(a,?x),e) -> false retract eq(q(q(a,?y_1),?z_1),e) -> false Polynomial Interpretation: a:= 0 e:= (6) q:= (1)*x1+(2)*x1*x2+(1)*x2 eq:= (5)+(1)*x1+(1)*x2 false:= (4) retract q(e,?x) -> ?x retract eq(e,q(a,?x)) -> false retract eq(e,q(q(a,?y_1),?z_1)) -> false retract eq(q(a,?x),e) -> false retract eq(q(q(a,?y_1),?z_1),e) -> false Polynomial Interpretation: a:= 0 e:= (6) q:= (2)+(2)*x1+(1)*x1*x2+(2)*x2 eq:= (14)+(6)*x1*x1+(11)*x1*x2+(6)*x2*x2 false:= (4) relatively terminating S/P: relatively terminating check CP condition: failed failure(Step 9) failure(no possibility remains) unknown Reduction-Preserving Completion Direct Methods: Can't judge Try Persistent Decomposition for... [ q(e,?x) -> ?x, q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(?x,?y) -> eq(?y,?x) ] Sort Assignment: a : =>19 e : =>19 q : 19*19=>19 eq : 19*19=>22 false : =>22 maximal types: {19,22} Persistent Decomposition failed: Can't judge Try Layer Preserving Decomposition for... [ q(e,?x) -> ?x, q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(?x,?y) -> eq(?y,?x) ] Layer Preserving Decomposition failed: Can't judge Try Commutative Decomposition for... [ q(e,?x) -> ?x, q(q(?x,?y),?z) -> q(?x,q(?y,?z)), q(?x,q(?y,?z)) -> q(q(?x,?y),?z), eq(e,q(a,?x)) -> false, eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(?x,?y) -> eq(?y,?x) ] Outside Critical Pair: by Rules <2, 0> develop reducts from lhs term... <{1}, q(e,q(?y_2,?z_2))> <{0}, q(?y_2,?z_2)> <{}, q(q(e,?y_2),?z_2)> develop reducts from rhs term... <{}, q(?y_2,?z_2)> Outside Critical Pair: by Rules <2, 1> develop reducts from lhs term... <{1}, q(q(?x_1,?y_1),q(?y_2,?z_2))> <{1}, q(q(?x_1,q(?y_1,?y_2)),?z_2)> <{}, q(q(q(?x_1,?y_1),?y_2),?z_2)> develop reducts from rhs term... <{2}, q(q(?x_1,?y_1),q(?y_2,?z_2))> <{2}, q(?x_1,q(q(?y_1,?y_2),?z_2))> <{}, q(?x_1,q(?y_1,q(?y_2,?z_2)))> Outside Critical Pair: by Rules <5, 3> develop reducts from lhs term... <{5}, eq(e,q(a,?x_3))> <{}, eq(q(a,?x_3),e)> develop reducts from rhs term... <{}, false> Outside Critical Pair: by Rules <5, 4> develop reducts from lhs term... <{5}, eq(q(a,?x_4),q(a,?y_4))> <{4}, eq(?y_4,?x_4)> <{}, eq(q(a,?y_4),q(a,?x_4))> develop reducts from rhs term... <{5}, eq(?y_4,?x_4)> <{}, eq(?x_4,?y_4)> Inside Critical Pair: by Rules <0, 1> develop reducts from lhs term... <{}, q(?x,?z_1)> develop reducts from rhs term... <{2}, q(q(e,?x),?z_1)> <{0}, q(?x,?z_1)> <{}, q(e,q(?x,?z_1))> Inside Critical Pair: by Rules <2, 1> develop reducts from lhs term... <{1}, q(q(?x_2,?y_2),q(?z_2,?z_1))> <{1}, q(q(?x_2,q(?y_2,?z_2)),?z_1)> <{}, q(q(q(?x_2,?y_2),?z_2),?z_1)> develop reducts from rhs term... <{2}, q(q(?x_2,q(?y_2,?z_2)),?z_1)> <{1}, q(?x_2,q(?y_2,q(?z_2,?z_1)))> <{}, q(?x_2,q(q(?y_2,?z_2),?z_1))> Inside Critical Pair: by Rules <0, 2> develop reducts from lhs term... <{}, q(?x_2,?x)> develop reducts from rhs term... <{1}, q(?x_2,q(e,?x))> <{}, q(q(?x_2,e),?x)> Inside Critical Pair: by Rules <1, 2> develop reducts from lhs term... <{2}, q(q(?x_2,?x_1),q(?y_1,?z_1))> <{2}, q(?x_2,q(q(?x_1,?y_1),?z_1))> <{}, q(?x_2,q(?x_1,q(?y_1,?z_1)))> develop reducts from rhs term... <{1}, q(?x_2,q(q(?x_1,?y_1),?z_1))> <{2}, q(q(q(?x_2,?x_1),?y_1),?z_1)> <{}, q(q(?x_2,q(?x_1,?y_1)),?z_1)> Inside Critical Pair: by Rules <2, 3> develop reducts from lhs term... <{1,5}, eq(q(a,q(?y_2,?z_2)),e)> <{5}, eq(q(q(a,?y_2),?z_2),e)> <{1}, eq(e,q(a,q(?y_2,?z_2)))> <{}, eq(e,q(q(a,?y_2),?z_2))> develop reducts from rhs term... <{}, false> Inside Critical Pair: by Rules <2, 4> develop reducts from lhs term... <{1,5}, eq(q(a,?y_4),q(a,q(?y_2,?z_2)))> <{5}, eq(q(a,?y_4),q(q(a,?y_2),?z_2))> <{1}, eq(q(a,q(?y_2,?z_2)),q(a,?y_4))> <{}, eq(q(q(a,?y_2),?z_2),q(a,?y_4))> develop reducts from rhs term... <{5}, eq(?y_4,q(?y_2,?z_2))> <{}, eq(q(?y_2,?z_2),?y_4)> Inside Critical Pair: by Rules <2, 4> develop reducts from lhs term... <{1,5}, eq(q(a,q(?y_2,?z_2)),q(a,?x_4))> <{5}, eq(q(q(a,?y_2),?z_2),q(a,?x_4))> <{1}, eq(q(a,?x_4),q(a,q(?y_2,?z_2)))> <{}, eq(q(a,?x_4),q(q(a,?y_2),?z_2))> develop reducts from rhs term... <{5}, eq(q(?y_2,?z_2),?x_4)> <{}, eq(?x_4,q(?y_2,?z_2))> Try A Minimal Decomposition {4,3,5,0,2}{1} {4,3,5,0,2} (cm)Rewrite Rules: [ eq(q(a,?x),q(a,?y)) -> eq(?x,?y), eq(e,q(a,?x)) -> false, eq(?x,?y) -> eq(?y,?x), q(e,?x) -> ?x, q(?x,q(?y,?z)) -> q(q(?x,?y),?z) ] Apply Direct Methods... Inner CPs: [ eq(q(q(a,?y_4),?z_4),q(a,?y)) = eq(q(?y_4,?z_4),?y), eq(q(a,?x),q(q(a,?y_4),?z_4)) = eq(?x,q(?y_4,?z_4)), eq(e,q(q(a,?y_4),?z_4)) = false, q(?x_4,?x_3) = q(q(?x_4,e),?x_3), q(?x_1,q(q(?x,?y),?z)) = q(q(?x_1,?x),q(?y,?z)) ] Outer CPs: [ eq(?x,?y) = eq(q(a,?y),q(a,?x)), false = eq(q(a,?x_1),e), q(?y_4,?z_4) = q(q(e,?y_4),?z_4) ] not Overlay, check Termination... unknown/not Terminating unknown Knuth & Bendix Linear unknown Development Closed unknown Strongly Closed unknown Weakly-Non-Overlapping & Non-Collapsing & Shallow unknown Upside-Parallel-Closed/Outside-Closed (inner) Parallel CPs: (not computed) unknown Toyama (Parallel CPs) Simultaneous CPs: [ eq(q(q(a,?y_10),?z_10),q(q(a,?y_5),?z_5)) = eq(q(?y_5,?z_5),q(?y_10,?z_10)), eq(q(a,?y),q(q(a,?y_5),?z_5)) = eq(q(?y_5,?z_5),?y), eq(q(q(a,?y_5),?z_5),q(a,?x)) = eq(?x,q(?y_5,?z_5)), eq(q(q(a,?y_5),?z_5),q(q(a,?y_10),?z_10)) = eq(q(?y_5,?z_5),q(?y_10,?z_10)), eq(q(a,?y),q(a,?x)) = eq(?x,?y), eq(q(q(a,?y_5),?z_5),q(a,?y)) = eq(q(?y_5,?z_5),?y), eq(q(a,?x),q(q(a,?y_5),?z_5)) = eq(?x,q(?y_5,?z_5)), eq(q(q(a,?y_5),?z_5),e) = false, eq(q(a,?x),e) = false, eq(e,q(q(a,?y_5),?z_5)) = false, eq(?x_1,?y_1) = eq(q(a,?y_1),q(a,?x_1)), false = eq(q(a,?x_2),e), q(q(e,?y_4),?z_4) = q(?y_4,?z_4), q(q(?x_5,e),?x) = q(?x_5,?x), q(q(?y,?y_1),?z_1) = q(q(e,?y),q(?y_1,?z_1)), ?z = q(q(e,e),?z), q(?y,?z) = q(q(e,?y),?z), q(?x,q(q(?y,?y_1),?z_1)) = q(q(?x,?y),q(?y_1,?z_1)), q(?x,?z) = q(q(?x,e),?z), q(q(?x_1,?x),q(q(?y,?y_2),?z_2)) = q(?x_1,q(q(?x,?y),q(?y_2,?z_2))), q(q(?x_1,?x),?z) = q(?x_1,q(q(?x,e),?z)), eq(q(q(?y,?y_3),?z_3),?y_2) = eq(q(q(a,?y),q(?y_3,?z_3)),q(a,?y_2)), eq(?z,?y_2) = eq(q(q(a,e),?z),q(a,?y_2)), eq(?x_2,q(q(?y,?y_3),?z_3)) = eq(q(a,?x_2),q(q(a,?y),q(?y_3,?z_3))), eq(?x_2,?z) = eq(q(a,?x_2),q(q(a,e),?z)), false = eq(e,q(q(a,?y),q(?y_1,?z_1))), false = eq(e,q(q(a,e),?z)), q(q(?x_1,?x),q(?y,?z)) = q(?x_1,q(q(?x,?y),?z)), eq(q(?y,?z),?y_2) = eq(q(q(a,?y),?z),q(a,?y_2)), eq(?x_2,q(?y,?z)) = eq(q(a,?x_2),q(q(a,?y),?z)), false = eq(e,q(q(a,?y),?z)) ] unknown Okui (Simultaneous CPs) unknown Strongly Depth-Preserving & Root-E-Closed/Non-E-Overlapping unknown Strongly Weight-Preserving & Root-E-Closed/Non-E-Overlapping check Locally Decreasing Diagrams by Rule Labelling... Critical Pair by Rules <4, 0> preceded by [(eq,1)] unknown Diagram Decreasing check Non-Confluence... obtain 15 rules by 3 steps unfolding strenghten q(e,?x_3) and ?x_3 strenghten eq(?x_7,?y_7) and eq(?y_7,?x_7) strenghten q(q(e,e),?x_10) and ?x_10 strenghten eq(e,q(a,?x_1)) and false strenghten eq(q(a,?x_1),e) and false strenghten q(q(?x_4,e),?x_3) and q(?x_4,?x_3) strenghten q(q(e,?y_4),?z_4) and q(?y_4,?z_4) strenghten eq(e,q(q(a,?y_4),?z_4)) and false strenghten q(e,q(q(e,?y_4),?z_4)) and q(?y_4,?z_4) strenghten q(q(?x_4,e),q(e,?x_10)) and q(?x_4,?x_10) strenghten eq(q(a,?x),q(a,?y)) and eq(?x,?y) strenghten eq(q(a,?y),q(a,?x)) and eq(?x,?y) strenghten q(q(?x_1,?x),q(?y,?z)) and q(?x_1,q(q(?x,?y),?z)) strenghten eq(q(a,?x),q(q(a,?y_4),?z_4)) and eq(?x,q(?y_4,?z_4)) strenghten eq(q(q(a,?y_4),?z_4),q(a,?y)) and eq(q(?y_4,?z_4),?y) obtain 26 candidates for checking non-joinability check by TCAP-Approximation (success) Witness for Non-Confluence: Direct Methods: not CR {1} (cm)Rewrite Rules: [ q(q(?x,?y),?z) -> q(?x,q(?y,?z)) ] Apply Direct Methods... Inner CPs: [ q(q(?x,q(?y,?z)),?z_1) = q(q(?x,?y),q(?z,?z_1)) ] Outer CPs: [ ] not Overlay, check Termination... Terminating, WCR Knuth & Bendix Direct Methods: CR Commutative Decomposition failed: Can't judge No further decomposition possible Final result: Can't judge R10.trs: Failure(unknown) (18171 msec.)