(ignored inputs)COMMENT doi:10.4230/LIPIcs.RTA.2013.319 [115] Example 4.1 submitted by: Aart Middeldorp Rewrite Rules: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x, +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Apply Direct Methods... Inner CPs: [ +(?x_2,a) = +(+(?x_2,a),?x), +(?x_2,a) = +(+(?x_2,b),g(a)), +(?x_2,?x_1) = +(+(?x_2,0),?x_1), +(?x_2,+(?x_3,+(?y_3,?z_3))) = +(+(?x_2,+(?x_3,?y_3)),?z_3), +(?x_2,+(?y_4,?x_4)) = +(+(?x_2,?x_4),?y_4), +(a,?z_3) = +(a,+(?x,?z_3)), +(a,?z_3) = +(b,+(g(a),?z_3)), +(?x_1,?z_3) = +(0,+(?x_1,?z_3)), +(+(+(?x_2,?y_2),?z_2),?z_3) = +(?x_2,+(+(?y_2,?z_2),?z_3)), +(+(?y_4,?x_4),?z_3) = +(?x_4,+(?y_4,?z_3)), +(?x_1,+(+(?x,?y),?z)) = +(+(?x_1,?x),+(?y,?z)), +(+(?x,+(?y,?z)),?z_1) = +(+(?x,?y),+(?z,?z_1)) ] Outer CPs: [ a = +(+(a,?y_2),?z_2), a = +(?x,a), a = +(g(a),b), +(?y_2,?z_2) = +(+(0,?y_2),?z_2), ?x_1 = +(?x_1,0), +(+(+(?x_3,?y_3),?y_2),?z_2) = +(?x_3,+(?y_3,+(?y_2,?z_2))), +(+(?x_2,?y_2),?z_2) = +(+(?y_2,?z_2),?x_2), +(?x_3,+(?y_3,?z_3)) = +(?z_3,+(?x_3,?y_3)) ] 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: [ +(+(a,?y_2),?z_2) = a, +(?x,a) = a, +(+(?x_3,a),?x) = +(?x_3,a), +(a,+(?x,?z_4)) = +(a,?z_4), +(g(a),b) = a, +(+(?x_2,b),g(a)) = +(?x_2,a), +(b,+(g(a),?z_3)) = +(a,?z_3), +(+(0,?y_2),?z_2) = +(?y_2,?z_2), +(?x,0) = ?x, +(+(?x_3,0),?x) = +(?x_3,?x), +(0,+(?x,?z_4)) = +(?x,?z_4), a = +(+(a,?y),+(?y_1,?z_1)), a = +(+(a,a),?z), a = +(+(a,b),g(a)), a = +(+(a,0),?z), a = +(+(a,+(?x_4,?y_4)),?z), a = +(+(a,?y),?z), +(+(?y,?y_1),?z_1) = +(+(0,?y),+(?y_1,?z_1)), a = +(+(0,a),?z), a = +(+(0,b),g(a)), ?z = +(+(0,0),?z), +(?x_4,+(?y_4,?z)) = +(+(0,+(?x_4,?y_4)),?z), +(?z,?y) = +(+(0,?y),?z), +(?x_3,+(?y_3,+(+(?y,?y_4),?z_4))) = +(+(+(?x_3,?y_3),?y),+(?y_4,?z_4)), +(?x_3,+(?y_3,a)) = +(+(+(?x_3,?y_3),a),?z), +(?x_3,+(?y_3,a)) = +(+(+(?x_3,?y_3),b),g(a)), +(?x_3,+(?y_3,?z)) = +(+(+(?x_3,?y_3),0),?z), +(?x_3,+(?y_3,+(?x_7,+(?y_7,?z)))) = +(+(+(?x_3,?y_3),+(?x_7,?y_7)),?z), +(?x_3,+(?y_3,+(?z,?y))) = +(+(+(?x_3,?y_3),?y),?z), +(+(+(?y,?y_1),?z_1),?x) = +(+(?x,?y),+(?y_1,?z_1)), +(a,?x) = +(+(?x,a),?z), +(a,?x) = +(+(?x,b),g(a)), +(?z,?x) = +(+(?x,0),?z), +(+(?x_4,+(?y_4,?z)),?x) = +(+(?x,+(?x_4,?y_4)),?z), +(+(?z,?y),?x) = +(+(?x,?y),?z), +(?y,?z) = +(+(0,?y),?z), +(?x_3,+(?y_3,+(?y,?z))) = +(+(+(?x_3,?y_3),?y),?z), +(+(?y,?z),?x) = +(+(?x,?y),?z), +(?x,+(+(?y,?y_1),?z_1)) = +(+(?x,?y),+(?y_1,?z_1)), +(?x,a) = +(+(?x,a),?z), +(?x,a) = +(+(?x,b),g(a)), +(?x,?z) = +(+(?x,0),?z), +(?x,+(?x_4,+(?y_4,?z))) = +(+(?x,+(?x_4,?y_4)),?z), +(?x,+(?z,?y)) = +(+(?x,?y),?z), +(+(?x_1,?x),+(+(?y,?y_2),?z_2)) = +(?x_1,+(+(?x,?y),+(?y_2,?z_2))), +(+(?x_1,?x),a) = +(?x_1,+(+(?x,a),?z)), +(+(?x_1,?x),a) = +(?x_1,+(+(?x,b),g(a))), +(+(?x_1,?x),?z) = +(?x_1,+(+(?x,0),?z)), +(+(?x_1,?x),+(?x_5,+(?y_5,?z))) = +(?x_1,+(+(?x,+(?x_5,?y_5)),?z)), +(+(?x_1,?x),+(?z,?y)) = +(?x_1,+(+(?x,?y),?z)), +(?x,+(+(+(?y,?y_5),?z_5),?z_4)) = +(+(+(?x,?y),+(?y_5,?z_5)),?z_4), +(?x,+(a,?z_4)) = +(+(+(?x,a),?z),?z_4), +(?x,+(a,?z_4)) = +(+(+(?x,b),g(a)),?z_4), +(?x,+(?z,?z_4)) = +(+(+(?x,0),?z),?z_4), +(?x,+(+(?x_8,+(?y_8,?z)),?z_4)) = +(+(+(?x,+(?x_8,?y_8)),?z),?z_4), +(?x,+(+(?z,?y),?z_4)) = +(+(+(?x,?y),?z),?z_4), +(+(?x_1,?x),+(?y,?z)) = +(?x_1,+(+(?x,?y),?z)), +(?x,+(+(?y,?z),?z_4)) = +(+(+(?x,?y),?z),?z_4), +(+(+(?x_4,+(?y_4,?y)),?y_3),?z_3) = +(+(?x_4,?y_4),+(?y,+(?y_3,?z_3))), +(+(a,?y_3),?z_3) = +(a,+(?y,+(?y_3,?z_3))), +(+(a,?y_3),?z_3) = +(b,+(g(a),+(?y_3,?z_3))), +(+(?y,?y_3),?z_3) = +(0,+(?y,+(?y_3,?z_3))), +(+(+(+(?x,?y_7),?z_7),?y_3),?z_3) = +(?x,+(+(?y_7,?z_7),+(?y_3,?z_3))), +(+(+(?y,?x),?y_3),?z_3) = +(?x,+(?y,+(?y_3,?z_3))), +(?z,+(?x_1,+(?y_1,?y))) = +(+(?x_1,?y_1),+(?y,?z)), +(?z,a) = +(a,+(?y,?z)), +(?z,a) = +(b,+(g(a),?z)), +(?z,?y) = +(0,+(?y,?z)), +(?z,+(+(?x,?y_4),?z_4)) = +(?x,+(+(?y_4,?z_4),?z)), +(?z,+(?y,?x)) = +(?x,+(?y,?z)), +(+(+(?x,?y),?y_3),?z_3) = +(?x,+(?y,+(?y_3,?z_3))), +(?z,+(?x,?y)) = +(?x,+(?y,?z)), +(+(?x_1,+(?y_1,?y)),?z) = +(+(?x_1,?y_1),+(?y,?z)), +(a,?z) = +(a,+(?y,?z)), +(a,?z) = +(b,+(g(a),?z)), +(?y,?z) = +(0,+(?y,?z)), +(+(+(?x,?y_4),?z_4),?z) = +(?x,+(+(?y_4,?z_4),?z)), +(+(?y,?x),?z) = +(?x,+(?y,?z)), +(+(?x_2,+(?y_2,?y)),+(?z,?z_1)) = +(+(+(?x_2,?y_2),+(?y,?z)),?z_1), +(a,+(?z,?z_1)) = +(+(a,+(?y,?z)),?z_1), +(a,+(?z,?z_1)) = +(+(b,+(g(a),?z)),?z_1), +(+(+(?x,?y_5),?z_5),+(?z,?z_1)) = +(+(?x,+(+(?y_5,?z_5),?z)),?z_1), +(+(?y,?x),+(?z,?z_1)) = +(+(?x,+(?y,?z)),?z_1), +(+(?x_4,+(?x_5,+(?y_5,?y))),?z) = +(?x_4,+(+(?x_5,?y_5),+(?y,?z))), +(+(?x_4,a),?z) = +(?x_4,+(a,+(?y,?z))), +(+(?x_4,a),?z) = +(?x_4,+(b,+(g(a),?z))), +(+(?x_4,?y),?z) = +(?x_4,+(0,+(?y,?z))), +(+(?x_4,+(+(?x,?y_8),?z_8)),?z) = +(?x_4,+(?x,+(+(?y_8,?z_8),?z))), +(+(?x_4,+(?y,?x)),?z) = +(?x_4,+(?x,+(?y,?z))), +(+(?x,?y),+(?z,?z_1)) = +(+(?x,+(?y,?z)),?z_1), +(+(?x_4,+(?x,?y)),?z) = +(?x_4,+(?x,+(?y,?z))), a = +(?y,a), a = +(g(a),b), ?y = +(?y,0), +(+(?x,?y_3),?z_3) = +(+(?y_3,?z_3),?x), +(?x_4,+(?y_4,?y)) = +(?y,+(?x_4,?y_4)), +(+(?x_4,?x),?y) = +(?x_4,+(?y,?x)), +(?x,+(?y,?z_5)) = +(+(?y,?x),?z_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 <+(?x_2,a), +(+(?x_2,a),?x)> by Rules <0, 3> preceded by [(+,2)] joinable by a reduction of rules <[], [([],4),([(+,2)],0)]> Critical Pair <+(?x_2,a), +(+(?x_2,b),g(a))> by Rules <1, 3> preceded by [(+,2)] joinable by a reduction of rules <[], [([],4),([(+,2)],1)]> Critical Pair <+(?x_2,?x_1), +(+(?x_2,0),?x_1)> by Rules <2, 3> preceded by [(+,2)] joinable by a reduction of rules <[], [([(+,1)],5),([(+,1)],2)]> joinable by a reduction of rules <[], [([],4),([(+,2)],2)]> Critical Pair <+(?x_2,+(?x_3,+(?y_3,?z_3))), +(+(?x_2,+(?x_3,?y_3)),?z_3)> by Rules <4, 3> preceded by [(+,2)] joinable by a reduction of rules <[([(+,2)],3)], [([],4)]> Critical Pair <+(?x_2,+(?y_4,?x_4)), +(+(?x_2,?x_4),?y_4)> by Rules <5, 3> preceded by [(+,2)] joinable by a reduction of rules <[([(+,2)],5)], [([],4)]> Critical Pair <+(a,?z_3), +(a,+(?x,?z_3))> by Rules <0, 4> preceded by [(+,1)] joinable by a reduction of rules <[([],0)], [([],0)]> Critical Pair <+(a,?z_3), +(b,+(g(a),?z_3))> by Rules <1, 4> preceded by [(+,1)] joinable by a reduction of rules <[], [([],3),([(+,1)],1)]> Critical Pair <+(?x_1,?z_3), +(0,+(?x_1,?z_3))> by Rules <2, 4> preceded by [(+,1)] joinable by a reduction of rules <[], [([],2)]> Critical Pair <+(+(+(?x_2,?y_2),?z_2),?z_3), +(?x_2,+(+(?y_2,?z_2),?z_3))> by Rules <3, 4> preceded by [(+,1)] joinable by a reduction of rules <[([(+,1)],4)], [([],3)]> Critical Pair <+(+(?y_4,?x_4),?z_3), +(?x_4,+(?y_4,?z_3))> by Rules <5, 4> preceded by [(+,1)] joinable by a reduction of rules <[([(+,1)],5)], [([],3)]> Critical Pair <+(?x_1,+(+(?x,?y),?z)), +(+(?x_1,?x),+(?y,?z))> by Rules <3, 3> preceded by [(+,2)] joinable by a reduction of rules <[([(+,2)],4)], [([],4)]> Critical Pair <+(+(?x,+(?y,?z)),?z_1), +(+(?x,?y),+(?z,?z_1))> by Rules <4, 4> preceded by [(+,1)] joinable by a reduction of rules <[([(+,1)],3)], [([],3)]> Critical Pair <+(+(a,?y_2),?z_2), a> by Rules <3, 0> preceded by [] joinable by a reduction of rules <[([(+,1)],0),([],0)], []> joinable by a reduction of rules <[([],4),([],0)], []> Critical Pair <+(?y_4,a), a> by Rules <5, 0> preceded by [] joinable by a reduction of rules <[([],5),([],0)], []> Critical Pair <+(g(a),b), a> by Rules <5, 1> preceded by [] joinable by a reduction of rules <[([],5),([],1)], []> Critical Pair <+(+(0,?y_2),?z_2), +(?y_2,?z_2)> by Rules <3, 2> preceded by [] joinable by a reduction of rules <[([(+,1)],2)], []> Critical Pair <+(?y_4,0), ?y_4> by Rules <5, 2> preceded by [] joinable by a reduction of rules <[([],5),([],2)], []> Critical Pair <+(?x_3,+(?y_3,+(?y_2,?z_2))), +(+(+(?x_3,?y_3),?y_2),?z_2)> by Rules <4, 3> preceded by [] joinable by a reduction of rules <[([],3)], [([],4)]> Critical Pair <+(+(?y_2,?z_2),?x_4), +(+(?x_4,?y_2),?z_2)> by Rules <5, 3> preceded by [] joinable by a reduction of rules <[([],5)], [([],4)]> Critical Pair <+(?y_4,+(?x_3,?y_3)), +(?x_3,+(?y_3,?y_4))> by Rules <5, 4> preceded by [] joinable by a reduction of rules <[([],5)], [([],3)]> unknown Diagram Decreasing check Non-Confluence... obtain 9 rules by 3 steps unfolding obtain 100 candidates for checking non-joinability check by TCAP-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: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x ] [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Polynomial Interpretation: +:= (1)*x1+(1)*x2 0:= (8) a:= 0 b:= (10) g:= (4)*x1+(6)*x1*x1 retract +(b,g(a)) -> a retract +(0,?x) -> ?x Polynomial Interpretation: +:= (2)+(2)*x1+(1)*x1*x2+(2)*x2 0:= (12) a:= (4) b:= 0 g:= (12)+(8)*x1+(6)*x1*x1 relatively terminating unknown Huet (modulo AC) check by Reduction-Preserving Completion... STEP: 1 (parallel) S: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x ] P: [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] S: terminating CP(S,S): PCP_in(symP,S): CP(S,symP): <+(a,?z_1), +(a,+(?x,?z_1))> --> => yes --> => yes <+(?x_1,a), +(+(?x_1,a),?x)> --> <+(?x_1,a), +(+(?x_1,a),?x)> => no --> => no <+(a,?z), +(b,+(g(a),?z))> --> => no <+(?x,a), +(+(?x,b),g(a))> --> <+(?x,a), +(+(?x,b),g(a))> => no --> => no <+(?x,?z_1), +(0,+(?x,?z_1))> --> <+(?x,?z_1), +(?x,?z_1)> => yes <+(?y_1,?z_1), +(+(0,?y_1),?z_1)> --> <+(?y_1,?z_1), +(?y_1,?z_1)> => yes <+(?x_1,?x), +(+(?x_1,0),?x)> --> <+(?x_1,?x), +(+(?x_1,0),?x)> => no --> => no check joinability condition: check modulo reachablity from +(?x_1,a) to +(+(?x_1,a),?x): maybe not reachable check modulo reachablity from a to +(?x,a): maybe not reachable check modulo reachablity from a to +(b,+(g(a),?z)): maybe not reachable check modulo reachablity from +(?x,a) to +(+(?x,b),g(a)): maybe not reachable check modulo reachablity from a to +(g(a),b): maybe not reachable check modulo reachablity from +(?x_1,?x) to +(+(?x_1,0),?x): maybe not reachable check modulo reachablity from ?x to +(?x,0): maybe not reachable failed failure(Step 1) [ +(?x,a) -> a, +(g(a),b) -> a, +(?x,0) -> ?x ] Added S-Rules: [ +(?x,a) -> a, +(g(a),b) -> a, +(?x,0) -> ?x ] Added P-Rules: [ ] STEP: 2 (linear) S: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x ] P: [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] S: terminating CP(S,S): CP_in(symP,S): CP(S,symP): <+(a,?z_1), +(a,+(?x,?z_1))> --> => yes --> => yes <+(?x_1,a), +(+(?x_1,a),?x)> --> <+(?x_1,a), +(+(?x_1,a),?x)> => no --> => no <+(a,?z), +(b,+(g(a),?z))> --> => no <+(?x,a), +(+(?x,b),g(a))> --> <+(?x,a), +(+(?x,b),g(a))> => no --> => no <+(?x,?z_1), +(0,+(?x,?z_1))> --> <+(?x,?z_1), +(?x,?z_1)> => yes <+(?y_1,?z_1), +(+(0,?y_1),?z_1)> --> <+(?y_1,?z_1), +(?y_1,?z_1)> => yes <+(?x_1,?x), +(+(?x_1,0),?x)> --> <+(?x_1,?x), +(+(?x_1,0),?x)> => no --> => no check joinability condition: check modulo reachablity from +(?x_1,a) to +(+(?x_1,a),?x): maybe not reachable check modulo reachablity from a to +(?x,a): maybe not reachable check modulo reachablity from a to +(b,+(g(a),?z)): maybe not reachable check modulo reachablity from +(?x,a) to +(+(?x,b),g(a)): maybe not reachable check modulo reachablity from a to +(g(a),b): maybe not reachable check modulo reachablity from +(?x_1,?x) to +(+(?x_1,0),?x): maybe not reachable check modulo reachablity from ?x to +(?x,0): maybe not reachable failed failure(Step 2) [ +(?x,a) -> a, +(g(a),b) -> a, +(?x,0) -> ?x ] Added S-Rules: [ +(?x,a) -> a, +(g(a),b) -> a, +(?x,0) -> ?x ] Added P-Rules: [ ] STEP: 3 (relative) S: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x ] P: [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Check relative termination: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x ] [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Polynomial Interpretation: +:= (1)*x1+(1)*x2 0:= (8) a:= 0 b:= (10) g:= (4)*x1+(6)*x1*x1 retract +(b,g(a)) -> a retract +(0,?x) -> ?x Polynomial Interpretation: +:= (2)+(2)*x1+(1)*x1*x2+(2)*x2 0:= (12) a:= (4) b:= 0 g:= (12)+(8)*x1+(6)*x1*x1 relatively terminating S/P: relatively terminating check CP condition: failed failure(Step 3) STEP: 4 (parallel) S: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x, +(?x,a) -> a, +(g(a),b) -> a, +(?x,0) -> ?x ] P: [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] S: terminating CP(S,S): --> => yes --> => yes --> => yes <0, 0> --> <0, 0> => yes --> => yes --> => yes --> => yes <0, 0> --> <0, 0> => yes PCP_in(symP,S): CP(S,symP): <+(a,?z_1), +(a,+(?x,?z_1))> --> => yes --> => yes <+(?x_1,a), +(+(?x_1,a),?x)> --> => yes --> => yes <+(a,?z), +(b,+(g(a),?z))> --> => no <+(?x,a), +(+(?x,b),g(a))> --> => no --> => yes <+(?x,?z_1), +(0,+(?x,?z_1))> --> <+(?x,?z_1), +(?x,?z_1)> => yes <+(?y_1,?z_1), +(+(0,?y_1),?z_1)> --> <+(?y_1,?z_1), +(?y_1,?z_1)> => yes <+(?x_1,?x), +(+(?x_1,0),?x)> --> <+(?x_1,?x), +(?x_1,?x)> => yes --> => yes --> => yes <+(a,?z_1), +(?x,+(a,?z_1))> --> => yes <+(?x_1,a), +(+(?x_1,?x),a)> --> => yes --> => yes <+(a,?z), +(g(a),+(b,?z))> --> => no <+(?x,a), +(+(?x,g(a)),b)> --> => no --> => yes <+(?x_1,?y_1), +(?x_1,+(?y_1,0))> --> <+(?x_1,?y_1), +(?x_1,?y_1)> => yes <+(?x,?z_1), +(?x,+(0,?z_1))> --> <+(?x,?z_1), +(?x,?z_1)> => yes <+(?x_1,?x), +(+(?x_1,?x),0)> --> <+(?x_1,?x), +(?x_1,?x)> => yes --> => yes check joinability condition: check modulo reachablity from a to +(b,+(g(a),?z)): maybe not reachable check modulo reachablity from a to +(+(?x,b),g(a)): maybe not reachable check modulo reachablity from a to +(g(a),+(b,?z)): maybe not reachable check modulo reachablity from a to +(+(?x,g(a)),b): maybe not reachable failed failure(Step 4) [ ] Added S-Rules: [ ] Added P-Rules: [ ] STEP: 5 (linear) S: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x, +(?x,a) -> a, +(g(a),b) -> a, +(?x,0) -> ?x ] P: [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] S: terminating CP(S,S): --> => yes --> => yes --> => yes <0, 0> --> <0, 0> => yes --> => yes --> => yes --> => yes <0, 0> --> <0, 0> => yes CP_in(symP,S): CP(S,symP): <+(a,?z_1), +(a,+(?x,?z_1))> --> => yes --> => yes <+(?x_1,a), +(+(?x_1,a),?x)> --> => yes --> => yes <+(a,?z), +(b,+(g(a),?z))> --> => no <+(?x,a), +(+(?x,b),g(a))> --> => no --> => yes <+(?x,?z_1), +(0,+(?x,?z_1))> --> <+(?x,?z_1), +(?x,?z_1)> => yes <+(?y_1,?z_1), +(+(0,?y_1),?z_1)> --> <+(?y_1,?z_1), +(?y_1,?z_1)> => yes <+(?x_1,?x), +(+(?x_1,0),?x)> --> <+(?x_1,?x), +(?x_1,?x)> => yes --> => yes --> => yes <+(a,?z_1), +(?x,+(a,?z_1))> --> => yes <+(?x_1,a), +(+(?x_1,?x),a)> --> => yes --> => yes <+(a,?z), +(g(a),+(b,?z))> --> => no <+(?x,a), +(+(?x,g(a)),b)> --> => no --> => yes <+(?x_1,?y_1), +(?x_1,+(?y_1,0))> --> <+(?x_1,?y_1), +(?x_1,?y_1)> => yes <+(?x,?z_1), +(?x,+(0,?z_1))> --> <+(?x,?z_1), +(?x,?z_1)> => yes <+(?x_1,?x), +(+(?x_1,?x),0)> --> <+(?x_1,?x), +(?x_1,?x)> => yes --> => yes check joinability condition: check modulo reachablity from a to +(b,+(g(a),?z)): maybe not reachable check modulo reachablity from a to +(+(?x,b),g(a)): maybe not reachable check modulo reachablity from a to +(g(a),+(b,?z)): maybe not reachable check modulo reachablity from a to +(+(?x,g(a)),b): maybe not reachable failed failure(Step 5) [ ] Added S-Rules: [ ] Added P-Rules: [ ] STEP: 6 (relative) S: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x, +(?x,a) -> a, +(g(a),b) -> a, +(?x,0) -> ?x ] P: [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Check relative termination: [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x, +(?x,a) -> a, +(g(a),b) -> a, +(?x,0) -> ?x ] [ +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Polynomial Interpretation: +:= (1)+(2)*x1+(2)*x1*x2+(2)*x2 0:= (12) a:= (9) b:= 0 g:= (11)+(2)*x1 retract +(b,g(a)) -> a retract +(0,?x) -> ?x retract +(g(a),b) -> a retract +(?x,0) -> ?x Polynomial Interpretation: +:= (1)+(2)*x1+(2)*x1*x2+(2)*x2 0:= (15) a:= (1) b:= 0 g:= (11)+(2)*x1*x1 relatively terminating S/P: relatively terminating check CP condition: failed failure(Step 6) failure(no possibility remains) unknown Reduction-Preserving Completion Direct Methods: Can't judge Try Persistent Decomposition for... [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x, +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Sort Assignment: + : 19*19=>19 0 : =>19 a : =>19 b : =>19 g : 19=>19 maximal types: {19} Persistent Decomposition failed: Can't judge Try Layer Preserving Decomposition for... [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x, +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Layer Preserving Decomposition failed: Can't judge Try Commutative Decomposition for... [ +(a,?x) -> a, +(b,g(a)) -> a, +(0,?x) -> ?x, +(?x,+(?y,?z)) -> +(+(?x,?y),?z), +(+(?x,?y),?z) -> +(?x,+(?y,?z)), +(?x,?y) -> +(?y,?x) ] Outside Critical Pair: <+(+(a,?y_2),?z_2), a> by Rules <3, 0> develop reducts from lhs term... <{5}, +(?z_2,+(?y_2,a))> <{0,5}, +(?z_2,a)> <{5}, +(?z_2,+(a,?y_2))> <{4}, +(a,+(?y_2,?z_2))> <{5}, +(+(?y_2,a),?z_2)> <{0}, +(a,?z_2)> <{}, +(+(a,?y_2),?z_2)> develop reducts from rhs term... <{}, a> Outside Critical Pair: <+(?y_4,a), a> by Rules <5, 0> develop reducts from lhs term... <{5}, +(a,?y_4)> <{}, +(?y_4,a)> develop reducts from rhs term... <{}, a> Outside Critical Pair: <+(g(a),b), a> by Rules <5, 1> develop reducts from lhs term... <{5}, +(b,g(a))> <{}, +(g(a),b)> develop reducts from rhs term... <{}, a> Outside Critical Pair: <+(+(0,?y_2),?z_2), +(?y_2,?z_2)> by Rules <3, 2> develop reducts from lhs term... <{5}, +(?z_2,+(?y_2,0))> <{2,5}, +(?z_2,?y_2)> <{5}, +(?z_2,+(0,?y_2))> <{4}, +(0,+(?y_2,?z_2))> <{5}, +(+(?y_2,0),?z_2)> <{2}, +(?y_2,?z_2)> <{}, +(+(0,?y_2),?z_2)> develop reducts from rhs term... <{5}, +(?z_2,?y_2)> <{}, +(?y_2,?z_2)> Outside Critical Pair: <+(?y_4,0), ?y_4> by Rules <5, 2> develop reducts from lhs term... <{5}, +(0,?y_4)> <{}, +(?y_4,0)> develop reducts from rhs term... <{}, ?y_4> Outside Critical Pair: <+(?x_3,+(?y_3,+(?y_2,?z_2))), +(+(+(?x_3,?y_3),?y_2),?z_2)> by Rules <4, 3> develop reducts from lhs term... <{5}, +(+(+(?z_2,?y_2),?y_3),?x_3)> <{5}, +(+(+(?y_2,?z_2),?y_3),?x_3)> <{3,5}, +(+(+(?y_3,?y_2),?z_2),?x_3)> <{5}, +(+(?y_3,+(?z_2,?y_2)),?x_3)> <{5}, +(+(?y_3,+(?y_2,?z_2)),?x_3)> <{3,5}, +(+(?x_3,?y_3),+(?z_2,?y_2))> <{3}, +(+(?x_3,?y_3),+(?y_2,?z_2))> <{5}, +(?x_3,+(+(?z_2,?y_2),?y_3))> <{5}, +(?x_3,+(+(?y_2,?z_2),?y_3))> <{3}, +(?x_3,+(+(?y_3,?y_2),?z_2))> <{5}, +(?x_3,+(?y_3,+(?z_2,?y_2)))> <{}, +(?x_3,+(?y_3,+(?y_2,?z_2)))> develop reducts from rhs term... <{5}, +(?z_2,+(?y_2,+(?y_3,?x_3)))> <{5}, +(?z_2,+(?y_2,+(?x_3,?y_3)))> <{4,5}, +(?z_2,+(?x_3,+(?y_3,?y_2)))> <{5}, +(?z_2,+(+(?y_3,?x_3),?y_2))> <{5}, +(?z_2,+(+(?x_3,?y_3),?y_2))> <{4,5}, +(+(?y_3,?x_3),+(?y_2,?z_2))> <{4}, +(+(?x_3,?y_3),+(?y_2,?z_2))> <{5}, +(+(?y_2,+(?y_3,?x_3)),?z_2)> <{5}, +(+(?y_2,+(?x_3,?y_3)),?z_2)> <{4}, +(+(?x_3,+(?y_3,?y_2)),?z_2)> <{5}, +(+(+(?y_3,?x_3),?y_2),?z_2)> <{}, +(+(+(?x_3,?y_3),?y_2),?z_2)> Outside Critical Pair: <+(+(?y_2,?z_2),?x_4), +(+(?x_4,?y_2),?z_2)> by Rules <5, 3> develop reducts from lhs term... <{5}, +(?x_4,+(?z_2,?y_2))> <{5}, +(?x_4,+(?y_2,?z_2))> <{4}, +(?y_2,+(?z_2,?x_4))> <{5}, +(+(?z_2,?y_2),?x_4)> <{}, +(+(?y_2,?z_2),?x_4)> develop reducts from rhs term... <{5}, +(?z_2,+(?y_2,?x_4))> <{5}, +(?z_2,+(?x_4,?y_2))> <{4}, +(?x_4,+(?y_2,?z_2))> <{5}, +(+(?y_2,?x_4),?z_2)> <{}, +(+(?x_4,?y_2),?z_2)> Outside Critical Pair: <+(?y_4,+(?x_3,?y_3)), +(?x_3,+(?y_3,?y_4))> by Rules <5, 4> develop reducts from lhs term... <{5}, +(+(?y_3,?x_3),?y_4)> <{5}, +(+(?x_3,?y_3),?y_4)> <{3}, +(+(?y_4,?x_3),?y_3)> <{5}, +(?y_4,+(?y_3,?x_3))> <{}, +(?y_4,+(?x_3,?y_3))> develop reducts from rhs term... <{5}, +(+(?y_4,?y_3),?x_3)> <{5}, +(+(?y_3,?y_4),?x_3)> <{3}, +(+(?x_3,?y_3),?y_4)> <{5}, +(?x_3,+(?y_4,?y_3))> <{}, +(?x_3,+(?y_3,?y_4))> Inside Critical Pair: <+(?x_2,a), +(+(?x_2,a),?x)> by Rules <0, 3> develop reducts from lhs term... <{5}, +(a,?x_2)> <{}, +(?x_2,a)> develop reducts from rhs term... <{5}, +(?x,+(a,?x_2))> <{5}, +(?x,+(?x_2,a))> <{4}, +(?x_2,+(a,?x))> <{5}, +(+(a,?x_2),?x)> <{}, +(+(?x_2,a),?x)> Inside Critical Pair: <+(?x_2,a), +(+(?x_2,b),g(a))> by Rules <1, 3> develop reducts from lhs term... <{5}, +(a,?x_2)> <{}, +(?x_2,a)> develop reducts from rhs term... <{5}, +(g(a),+(b,?x_2))> <{5}, +(g(a),+(?x_2,b))> <{4}, +(?x_2,+(b,g(a)))> <{5}, +(+(b,?x_2),g(a))> <{}, +(+(?x_2,b),g(a))> Inside Critical Pair: <+(?x_2,?x_1), +(+(?x_2,0),?x_1)> by Rules <2, 3> develop reducts from lhs term... <{5}, +(?x_1,?x_2)> <{}, +(?x_2,?x_1)> develop reducts from rhs term... <{5}, +(?x_1,+(0,?x_2))> <{5}, +(?x_1,+(?x_2,0))> <{4}, +(?x_2,+(0,?x_1))> <{5}, +(+(0,?x_2),?x_1)> <{}, +(+(?x_2,0),?x_1)> Inside Critical Pair: <+(?x_2,+(?x_3,+(?y_3,?z_3))), +(+(?x_2,+(?x_3,?y_3)),?z_3)> by Rules <4, 3> develop reducts from lhs term... <{5}, +(+(+(?z_3,?y_3),?x_3),?x_2)> <{5}, +(+(+(?y_3,?z_3),?x_3),?x_2)> <{3,5}, +(+(+(?x_3,?y_3),?z_3),?x_2)> <{5}, +(+(?x_3,+(?z_3,?y_3)),?x_2)> <{5}, +(+(?x_3,+(?y_3,?z_3)),?x_2)> <{3,5}, +(+(?x_2,?x_3),+(?z_3,?y_3))> <{3}, +(+(?x_2,?x_3),+(?y_3,?z_3))> <{5}, +(?x_2,+(+(?z_3,?y_3),?x_3))> <{5}, +(?x_2,+(+(?y_3,?z_3),?x_3))> <{3}, +(?x_2,+(+(?x_3,?y_3),?z_3))> <{5}, +(?x_2,+(?x_3,+(?z_3,?y_3)))> <{}, +(?x_2,+(?x_3,+(?y_3,?z_3)))> develop reducts from rhs term... <{5}, +(?z_3,+(+(?y_3,?x_3),?x_2))> <{5}, +(?z_3,+(+(?x_3,?y_3),?x_2))> <{3,5}, +(?z_3,+(+(?x_2,?x_3),?y_3))> <{5}, +(?z_3,+(?x_2,+(?y_3,?x_3)))> <{5}, +(?z_3,+(?x_2,+(?x_3,?y_3)))> <{4,5}, +(?x_2,+(+(?y_3,?x_3),?z_3))> <{4}, +(?x_2,+(+(?x_3,?y_3),?z_3))> <{5}, +(+(+(?y_3,?x_3),?x_2),?z_3)> <{5}, +(+(+(?x_3,?y_3),?x_2),?z_3)> <{3}, +(+(+(?x_2,?x_3),?y_3),?z_3)> <{5}, +(+(?x_2,+(?y_3,?x_3)),?z_3)> <{}, +(+(?x_2,+(?x_3,?y_3)),?z_3)> Inside Critical Pair: <+(?x_2,+(?y_4,?x_4)), +(+(?x_2,?x_4),?y_4)> by Rules <5, 3> develop reducts from lhs term... <{5}, +(+(?x_4,?y_4),?x_2)> <{5}, +(+(?y_4,?x_4),?x_2)> <{3}, +(+(?x_2,?y_4),?x_4)> <{5}, +(?x_2,+(?x_4,?y_4))> <{}, +(?x_2,+(?y_4,?x_4))> develop reducts from rhs term... <{5}, +(?y_4,+(?x_4,?x_2))> <{5}, +(?y_4,+(?x_2,?x_4))> <{4}, +(?x_2,+(?x_4,?y_4))> <{5}, +(+(?x_4,?x_2),?y_4)> <{}, +(+(?x_2,?x_4),?y_4)> Inside Critical Pair: <+(a,?z_3), +(a,+(?x,?z_3))> by Rules <0, 4> develop reducts from lhs term... <{5}, +(?z_3,a)> <{0}, a> <{}, +(a,?z_3)> develop reducts from rhs term... <{5}, +(+(?z_3,?x),a)> <{5}, +(+(?x,?z_3),a)> <{3}, +(+(a,?x),?z_3)> <{0}, a> <{5}, +(a,+(?z_3,?x))> <{}, +(a,+(?x,?z_3))> Inside Critical Pair: <+(a,?z_3), +(b,+(g(a),?z_3))> by Rules <1, 4> develop reducts from lhs term... <{5}, +(?z_3,a)> <{0}, a> <{}, +(a,?z_3)> develop reducts from rhs term... <{5}, +(+(?z_3,g(a)),b)> <{5}, +(+(g(a),?z_3),b)> <{3}, +(+(b,g(a)),?z_3)> <{5}, +(b,+(?z_3,g(a)))> <{}, +(b,+(g(a),?z_3))> Inside Critical Pair: <+(?x_1,?z_3), +(0,+(?x_1,?z_3))> by Rules <2, 4> develop reducts from lhs term... <{5}, +(?z_3,?x_1)> <{}, +(?x_1,?z_3)> develop reducts from rhs term... <{5}, +(+(?z_3,?x_1),0)> <{5}, +(+(?x_1,?z_3),0)> <{3}, +(+(0,?x_1),?z_3)> <{2,5}, +(?z_3,?x_1)> <{2}, +(?x_1,?z_3)> <{5}, +(0,+(?z_3,?x_1))> <{}, +(0,+(?x_1,?z_3))> Inside Critical Pair: <+(+(+(?x_2,?y_2),?z_2),?z_3), +(?x_2,+(+(?y_2,?z_2),?z_3))> by Rules <3, 4> develop reducts from lhs term... <{5}, +(?z_3,+(?z_2,+(?y_2,?x_2)))> <{5}, +(?z_3,+(?z_2,+(?x_2,?y_2)))> <{4,5}, +(?z_3,+(?x_2,+(?y_2,?z_2)))> <{5}, +(?z_3,+(+(?y_2,?x_2),?z_2))> <{5}, +(?z_3,+(+(?x_2,?y_2),?z_2))> <{4,5}, +(+(?y_2,?x_2),+(?z_2,?z_3))> <{4}, +(+(?x_2,?y_2),+(?z_2,?z_3))> <{5}, +(+(?z_2,+(?y_2,?x_2)),?z_3)> <{5}, +(+(?z_2,+(?x_2,?y_2)),?z_3)> <{4}, +(+(?x_2,+(?y_2,?z_2)),?z_3)> <{5}, +(+(+(?y_2,?x_2),?z_2),?z_3)> <{}, +(+(+(?x_2,?y_2),?z_2),?z_3)> develop reducts from rhs term... <{5}, +(+(?z_3,+(?z_2,?y_2)),?x_2)> <{5}, +(+(?z_3,+(?y_2,?z_2)),?x_2)> <{4,5}, +(+(?y_2,+(?z_2,?z_3)),?x_2)> <{5}, +(+(+(?z_2,?y_2),?z_3),?x_2)> <{5}, +(+(+(?y_2,?z_2),?z_3),?x_2)> <{3,5}, +(+(?x_2,+(?z_2,?y_2)),?z_3)> <{3}, +(+(?x_2,+(?y_2,?z_2)),?z_3)> <{5}, +(?x_2,+(?z_3,+(?z_2,?y_2)))> <{5}, +(?x_2,+(?z_3,+(?y_2,?z_2)))> <{4}, +(?x_2,+(?y_2,+(?z_2,?z_3)))> <{5}, +(?x_2,+(+(?z_2,?y_2),?z_3))> <{}, +(?x_2,+(+(?y_2,?z_2),?z_3))> Inside Critical Pair: <+(+(?y_4,?x_4),?z_3), +(?x_4,+(?y_4,?z_3))> by Rules <5, 4> develop reducts from lhs term... <{5}, +(?z_3,+(?x_4,?y_4))> <{5}, +(?z_3,+(?y_4,?x_4))> <{4}, +(?y_4,+(?x_4,?z_3))> <{5}, +(+(?x_4,?y_4),?z_3)> <{}, +(+(?y_4,?x_4),?z_3)> develop reducts from rhs term... <{5}, +(+(?z_3,?y_4),?x_4)> <{5}, +(+(?y_4,?z_3),?x_4)> <{3}, +(+(?x_4,?y_4),?z_3)> <{5}, +(?x_4,+(?z_3,?y_4))> <{}, +(?x_4,+(?y_4,?z_3))> Commutative Decomposition failed: Can't judge No further decomposition possible Combined result: Can't judge 538.trs: Failure(unknown CR) MAYBE (2465 msec.)