YES We show the termination of the TRS R: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) c(c(a(a(y,|0|()),x))) -> c(y) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(c(a(x,y)))) -> c#(c(c(y))) p3: c#(c(c(a(x,y)))) -> c#(c(y)) p4: c#(c(c(a(x,y)))) -> c#(y) p5: c#(c(b(c(y),|0|()))) -> c#(c(a(y,|0|()))) p6: c#(c(b(c(y),|0|()))) -> c#(a(y,|0|())) p7: c#(c(a(a(y,|0|()),x))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4, p5, p7} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(a(a(y,|0|()),x))) -> c#(y) p3: c#(c(b(c(y),|0|()))) -> c#(c(a(y,|0|()))) p4: c#(c(c(a(x,y)))) -> c#(y) p5: c#(c(c(a(x,y)))) -> c#(c(y)) p6: c#(c(c(a(x,y)))) -> c#(c(c(y))) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The set of usable rules consists of r1, r2, r3 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: c#_A(x1) = ((1,0),(0,0)) x1 + (71,0) c_A(x1) = ((1,1),(1,0)) x1 + (4,0) a_A(x1,x2) = x1 + ((1,1),(1,0)) x2 + (29,0) |0|_A() = (3,2) b_A(x1,x2) = x1 + (75,0) precedence: c# = c = |0| = b > a partial status: pi(c#) = [] pi(c) = [] pi(a) = [] pi(|0|) = [] pi(b) = [] The next rules are strictly ordered: p3 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(a(a(y,|0|()),x))) -> c#(y) p3: c#(c(c(a(x,y)))) -> c#(y) p4: c#(c(c(a(x,y)))) -> c#(c(y)) p5: c#(c(c(a(x,y)))) -> c#(c(c(y))) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4, p5} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(c(a(x,y)))) -> c#(c(c(y))) p3: c#(c(c(a(x,y)))) -> c#(c(y)) p4: c#(c(c(a(x,y)))) -> c#(y) p5: c#(c(a(a(y,|0|()),x))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The set of usable rules consists of r1, r2, r3 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: c#_A(x1) = ((1,0),(0,0)) x1 c_A(x1) = ((1,1),(1,1)) x1 + (12,1) a_A(x1,x2) = x1 + ((1,1),(1,1)) x2 + (8,13) |0|_A() = (1,2) b_A(x1,x2) = ((1,0),(1,0)) x1 + ((0,1),(0,0)) x2 + (27,21) precedence: c = |0| = b > c# = a partial status: pi(c#) = [] pi(c) = [1] pi(a) = [2] pi(|0|) = [] pi(b) = [] The next rules are strictly ordered: p2 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(c(a(x,y)))) -> c#(c(y)) p3: c#(c(c(a(x,y)))) -> c#(y) p4: c#(c(a(a(y,|0|()),x))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(a(a(y,|0|()),x))) -> c#(y) p3: c#(c(c(a(x,y)))) -> c#(y) p4: c#(c(c(a(x,y)))) -> c#(c(y)) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The set of usable rules consists of r1, r2, r3 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: c#_A(x1) = ((0,1),(0,1)) x1 + (9,0) c_A(x1) = ((0,1),(1,1)) x1 + (13,4) a_A(x1,x2) = ((1,1),(0,0)) x1 + ((0,1),(1,1)) x2 + (56,1) |0|_A() = (8,1) b_A(x1,x2) = x1 + ((1,1),(1,1)) x2 + (36,76) precedence: c# = c = a = |0| > b partial status: pi(c#) = [] pi(c) = [] pi(a) = [] pi(|0|) = [] pi(b) = [2] The next rules are strictly ordered: p4 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(a(a(y,|0|()),x))) -> c#(y) p3: c#(c(c(a(x,y)))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The estimated dependency graph contains the following SCCs: {p1, p2, p3} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(c(a(x,y)))) -> c#(y) p3: c#(c(a(a(y,|0|()),x))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The set of usable rules consists of r1, r2, r3 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: c#_A(x1) = x1 + (1,0) c_A(x1) = ((1,1),(1,1)) x1 a_A(x1,x2) = x1 + ((1,1),(1,1)) x2 + (0,11) |0|_A() = (2,3) b_A(x1,x2) = ((0,1),(0,1)) x1 + ((0,0),(1,1)) x2 + (0,44) precedence: |0| > c > b > c# = a partial status: pi(c#) = [1] pi(c) = [1] pi(a) = [2] pi(|0|) = [] pi(b) = [] The next rules are strictly ordered: p2 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(a(a(y,|0|()),x))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(a(x,y)))) -> c#(c(c(c(y)))) p2: c#(c(a(a(y,|0|()),x))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The set of usable rules consists of r1, r2, r3 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: c#_A(x1) = ((1,1),(0,1)) x1 + (4,38) c_A(x1) = ((0,1),(1,1)) x1 + (5,3) a_A(x1,x2) = ((1,1),(0,0)) x1 + ((0,1),(1,1)) x2 + (15,0) |0|_A() = (0,2) b_A(x1,x2) = ((0,0),(0,1)) x1 + ((0,1),(0,1)) x2 + (24,11) precedence: a > c > b > c# > |0| partial status: pi(c#) = [1] pi(c) = [] pi(a) = [] pi(|0|) = [] pi(b) = [] The next rules are strictly ordered: p1 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(a(a(y,|0|()),x))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(a(a(y,|0|()),x))) -> c#(y) and R consists of: r1: c(c(c(a(x,y)))) -> b(c(c(c(c(y)))),x) r2: c(c(b(c(y),|0|()))) -> a(|0|(),c(c(a(y,|0|())))) r3: c(c(a(a(y,|0|()),x))) -> c(y) The set of usable rules consists of (no rules) Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: c#_A(x1) = x1 + (4,3) c_A(x1) = ((1,0),(1,1)) x1 + (1,0) a_A(x1,x2) = x1 + ((1,0),(1,0)) x2 + (2,1) |0|_A() = (1,0) precedence: c = a > c# = |0| partial status: pi(c#) = [1] pi(c) = [] pi(a) = [] pi(|0|) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.