YES We show the termination of the TRS R: b(b(|0|(),y),x) -> y c(c(c(y))) -> c(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) a(y,|0|()) -> b(y,|0|()) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: c#(c(c(y))) -> c#(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) p2: c#(c(c(y))) -> c#(a(a(c(b(|0|(),y)),|0|()),|0|())) p3: c#(c(c(y))) -> a#(a(c(b(|0|(),y)),|0|()),|0|()) p4: c#(c(c(y))) -> a#(c(b(|0|(),y)),|0|()) p5: c#(c(c(y))) -> c#(b(|0|(),y)) p6: c#(c(c(y))) -> b#(|0|(),y) p7: a#(y,|0|()) -> b#(y,|0|()) and R consists of: r1: b(b(|0|(),y),x) -> y r2: c(c(c(y))) -> c(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) r3: a(y,|0|()) -> b(y,|0|()) 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(y))) -> c#(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) p2: c#(c(c(y))) -> c#(a(a(c(b(|0|(),y)),|0|()),|0|())) and R consists of: r1: b(b(|0|(),y),x) -> y r2: c(c(c(y))) -> c(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) r3: a(y,|0|()) -> b(y,|0|()) The set of usable rules consists of r1, r2, r3 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: c#_A(x1) = x1 + (0,4) c_A(x1) = ((1,0),(0,0)) x1 + (1,3) a_A(x1,x2) = x1 + (0,3) b_A(x1,x2) = x1 + x2 + (0,1) |0|_A() = (0,1) precedence: |0| > c > c# = a > b partial status: pi(c#) = [1] pi(c) = [] pi(a) = [] pi(b) = [1, 2] pi(|0|) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: c#_A(x1) = ((1,0),(0,0)) x1 + (0,3) c_A(x1) = (3,4) a_A(x1,x2) = (2,2) b_A(x1,x2) = x1 + x2 |0|_A() = (1,1) precedence: c# = c = |0| > a > b partial status: pi(c#) = [] pi(c) = [] pi(a) = [] pi(b) = [1] pi(|0|) = [] 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(y))) -> c#(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) and R consists of: r1: b(b(|0|(),y),x) -> y r2: c(c(c(y))) -> c(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) r3: a(y,|0|()) -> b(y,|0|()) 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(c(y))) -> c#(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) and R consists of: r1: b(b(|0|(),y),x) -> y r2: c(c(c(y))) -> c(c(a(a(c(b(|0|(),y)),|0|()),|0|()))) r3: a(y,|0|()) -> b(y,|0|()) The set of usable rules consists of r1, r2, r3 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: c#_A(x1) = ((0,1),(0,0)) x1 + (1,16) c_A(x1) = ((0,0),(1,0)) x1 + (16,1) a_A(x1,x2) = ((0,1),(0,1)) x1 + x2 + (1,6) b_A(x1,x2) = ((0,1),(0,1)) x1 + ((0,0),(1,1)) x2 + (1,1) |0|_A() = (2,1) precedence: c# > a = |0| > c > b partial status: pi(c#) = [] pi(c) = [] pi(a) = [2] pi(b) = [] pi(|0|) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: c#_A(x1) = (2,1) c_A(x1) = (3,1) a_A(x1,x2) = (4,2) b_A(x1,x2) = (1,2) |0|_A() = (5,3) precedence: a = b = |0| > c# = c partial status: pi(c#) = [] pi(c) = [] pi(a) = [] pi(b) = [] pi(|0|) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.