MAYBE (ignored inputs)COMMENT reduction failed Rewrite Rules: [ f(h(c,c)) -> a, a -> b, f(b) -> f(c), c -> f(c) ] Apply Direct Methods... Inner CPs: [ f(h(f(c),c)) = a, f(h(c,f(c))) = a ] Outer CPs: [ ] not Overlay, check Termination... unknown/not Terminating unknown Knuth & Bendix Linear unknown Development Closed unknown Strongly Closed unknown Weakly-Non-Overlapping & Non-Collapsing & Shallow inner CP cond (upside-parallel) innter CP Cond (outside) unknown Upside-Parallel-Closed/Outside-Closed (inner) Parallel CPs: (not computed) unknown Toyama (Parallel CPs) Simultaneous CPs: [ f(h(f(c),f(c))) = a, f(h(f(c),c)) = a, f(h(c,f(c))) = a, a = f(h(f(c),c)), a = f(h(c,f(c))) ] 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 <3, 0> preceded by [(f,1),(h,1)] unknown Diagram Decreasing check Non-Confluence... obtain 10 rules by 3 steps unfolding obtain 75 candidates for checking non-joinability check by TCAP-Approximation (failure) check by Ordering(rpo), check by Tree-Automata Approximation (success) where F = {(a,0),(b,0),(c,0),(f,1),(h,2)} Q = {q_0,q_1,q_{c},q_{f(c)},q_{h(c,f(c))}} Qf = {q_0,q_1} Delta = [ a -> q_1, b -> q_1, c -> q_{c}, f(q_{c}) -> q_{c}, f(q_{c}) -> q_{f(c)}, f(q_{h(c,f(c))}) -> q_0, h(q_{c},q_{f(c)}) -> q_{h(c,f(c))} ] (failure) check by Interpretation(mod2) (failure) check by Descendants-Approximation, check by Ordering(poly) (failure) unknown Non-Confluence unknown Huet (modulo AC) check by Reduction-Preserving Completion... failure(empty P) unknown Reduction-Preserving Completion check by Ordered Rewriting... remove redundants rules and split R-part: [ f(h(c,c)) -> a, a -> b, f(b) -> f(c), c -> f(c) ] E-part: [ ] ...failed to find a suitable LPO. unknown Confluence by Ordered Rewriting Direct Methods: Can't judge Try Persistent Decomposition for... [ f(h(c,c)) -> a, a -> b, f(b) -> f(c), c -> f(c) ] Sort Assignment: a : =>9 b : =>9 c : =>9 f : 9=>9 h : 9*9=>9 maximal types: {9} Persistent Decomposition failed: Can't judge Try Layer Preserving Decomposition for... [ f(h(c,c)) -> a, a -> b, f(b) -> f(c), c -> f(c) ] Layer Preserving Decomposition failed: Can't judge Try Commutative Decomposition for... [ f(h(c,c)) -> a, a -> b, f(b) -> f(c), c -> f(c) ] Inside Critical Pair: by Rules <3, 0> develop reducts from lhs term... <{3}, f(h(f(f(c)),f(c)))> <{3}, f(h(f(f(c)),c))> <{3}, f(h(f(c),f(c)))> <{}, f(h(f(c),c))> develop reducts from rhs term... <{1}, b> <{}, a> Inside Critical Pair: by Rules <3, 0> develop reducts from lhs term... <{3}, f(h(f(c),f(f(c))))> <{3}, f(h(f(c),f(c)))> <{3}, f(h(c,f(f(c))))> <{}, f(h(c,f(c)))> develop reducts from rhs term... <{1}, b> <{}, a> Try A Minimal Decomposition {0,3}{1}{2} {0,3} (cm)Rewrite Rules: [ f(h(c,c)) -> a, c -> f(c) ] Apply Direct Methods... Inner CPs: [ f(h(f(c),c)) = a, f(h(c,f(c))) = a ] Outer CPs: [ ] not Overlay, check Termination... unknown/not Terminating unknown Knuth & Bendix Linear unknown Development Closed unknown Strongly Closed unknown Weakly-Non-Overlapping & Non-Collapsing & Shallow inner CP cond (upside-parallel) innter CP Cond (outside) unknown Upside-Parallel-Closed/Outside-Closed (inner) Parallel CPs: (not computed) unknown Toyama (Parallel CPs) Simultaneous CPs: [ f(h(f(c),f(c))) = a, f(h(f(c),c)) = a, f(h(c,f(c))) = a, a = f(h(f(c),c)), a = f(h(c,f(c))) ] 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),(h,1)] unknown Diagram Decreasing check Non-Confluence... obtain 10 rules by 3 steps unfolding obtain 79 candidates for checking non-joinability check by TCAP-Approximation (failure) check by Ordering(rpo), check by Tree-Automata Approximation (success) where F = {(a,0),(c,0),(f,1),(h,2)} Q = {q_0,q_1,q_{c},q_{f(c)},q_{h(c,f(c))}} Qf = {q_0,q_1} Delta = [ a -> q_1, c -> q_{c}, f(q_{c}) -> q_{c}, f(q_{c}) -> q_{f(c)}, f(q_{h(c,f(c))}) -> q_0, h(q_{c},q_{f(c)}) -> q_{h(c,f(c))} ] (failure) check by Interpretation(mod2) (failure) check by Descendants-Approximation, check by Ordering(poly) (success) Polynomial Interpretation: a:= (8) c:= (1) f:= (3)+(1)*x1 h:= (2)+(1)*x2 [f(c)]-[c] = (3) >= 0 [a]-[f(h(c,c))] = (2) >= 0 [f(h(c,f(c)))]-[a] = (1) > 0 (success) Witness for Non-Confluence: a> Direct Methods: not CR {1} (cm)Rewrite Rules: [ a -> b ] Apply Direct Methods... Inner CPs: [ ] Outer CPs: [ ] Overlay, check Innermost Termination... Innermost Terminating (hence Terminating), WCR Knuth & Bendix Direct Methods: CR {2} (cm)Rewrite Rules: [ f(b) -> f(c) ] Apply Direct Methods... Inner CPs: [ ] Outer CPs: [ ] Overlay, check Innermost Termination... Innermost Terminating (hence Terminating), WCR Knuth & Bendix Direct Methods: CR Commutative Decomposition failed: Can't judge No further decomposition possible Combined result: Can't judge /tmp/filecswPfG.trs: Failure(unknown CR) (659 msec.)