YES (ignored inputs)COMMENT associative law + commutative law Rewrite Rules: [ f(f(?x,?y),?z) -> f(?x,f(?y,?z)), f(?x,?y) -> f(?y,?x) ] Apply Direct Methods... Inner CPs: [ f(f(?y_1,?x_1),?z) = f(?x_1,f(?y_1,?z)), f(f(?x,f(?y,?z)),?z_1) = f(f(?x,?y),f(?z,?z_1)) ] Outer CPs: [ f(?x,f(?y,?z)) = f(?z,f(?x,?y)) ] 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: [ f(?z,f(?x_1,f(?y_1,?y))) = f(f(?x_1,?y_1),f(?y,?z)), f(?z,f(?y,?x)) = f(?x,f(?y,?z)), f(?z,f(?x,?y)) = f(?x,f(?y,?z)), f(f(?x_1,f(?y_1,?y)),?z) = f(f(?x_1,?y_1),f(?y,?z)), f(f(?y,?x),?z) = f(?x,f(?y,?z)), f(f(?x_2,f(?y_2,?y)),f(?z,?z_1)) = f(f(f(?x_2,?y_2),f(?y,?z)),?z_1), f(f(?y,?x),f(?z,?z_1)) = f(f(?x,f(?y,?z)),?z_1), f(f(?x,?y),f(?z,?z_1)) = f(f(?x,f(?y,?z)),?z_1), f(?x_1,f(?y_1,?y)) = f(?y,f(?x_1,?y_1)), f(?x,f(?y,?z_2)) = f(f(?y,?x),?z_2) ] 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 <1, 0> preceded by [(f,1)] joinable by a reduction of rules <[([(f,1)],1),([],0)], []> joinable by a reduction of rules <[([],0),([(f,2)],1)], [([],1),([],0)]> Critical Pair by Rules <0, 0> preceded by [(f,1)] joinable by a reduction of rules <[([],0),([(f,2)],0)], [([],0)]> Critical Pair by Rules <1, 0> preceded by [] joinable by a reduction of rules <[([],1),([],0)], []> unknown Diagram Decreasing check Non-Confluence... obtain 12 rules by 3 steps unfolding strenghten f(?x_3,?y_3) and f(?y_3,?x_3) strenghten f(?x,f(?y,?x_4)) and f(?x_4,f(?x,?y)) strenghten f(?x,f(?y,?x_5)) and f(f(?x,?y),?x_5) strenghten f(?x_1,f(?x_10,?y_1)) and f(?x_10,f(?y_1,?x_1)) strenghten f(?x_1,f(?y_1,?x_12)) and f(?x_12,f(?y_1,?x_1)) strenghten f(?x_1,f(?y_1,?z)) and f(f(?y_1,?x_1),?z) strenghten f(?x_2,f(?x_10,?y_2)) and f(?x_10,f(?x_2,?y_2)) strenghten f(?x_6,f(?x_1,?y_1)) and f(?x_6,f(?y_1,?x_1)) strenghten f(f(?x_7,?y_7),?x_6) and f(?x_6,f(?x_7,?y_7)) strenghten f(f(?x_9,?y_9),?x_8) and f(?x_8,f(?y_9,?x_9)) strenghten f(f(?x_11,?y_11),?x_10) and f(?x_11,f(?x_10,?y_11)) strenghten f(f(?x_13,?y_13),?x_12) and f(?x_13,f(?y_13,?x_12)) strenghten f(f(?x_15,?y_15),?x_14) and f(?y_15,f(?x_14,?x_15)) strenghten f(f(?x_17,?y_17),?x_16) and f(?y_17,f(?x_17,?x_16)) strenghten f(?x,f(?x_2,f(?x_1,?y_1))) and f(?x_2,f(?x_1,f(?x,?y_1))) strenghten f(?x,f(?y,f(?x_7,?y_7))) and f(f(?x,?y),f(?x_7,?y_7)) strenghten f(?x,f(?y,f(?x_9,?y_9))) and f(f(?x,?y),f(?y_9,?x_9)) strenghten f(?x,f(?y,f(?x_11,?y_11))) and f(?x_11,f(f(?x,?y),?y_11)) obtain 100 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: [ ] [ f(f(?x,?y),?z) -> f(?x,f(?y,?z)), f(?x,?y) -> f(?y,?x) ] relatively terminating Huet (modulo AC) Direct Methods: CR Final result: CR 103.trs: Success(CR) (3456 msec.)