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: max/plus interpretations on natural numbers: c#_A(x1) = max{117, x1 + 7} c_A(x1) = max{176, x1 + 110} a_A(x1,x2) = max{170, x1 - 30, x2 + 55} b_A(x1,x2) = max{118, x1 - 30, x2 + 54} |0|_A = 47 precedence: c# = c > a > b = |0| partial status: pi(c#) = [1] pi(c) = [1] pi(a) = [2] pi(b) = [2] pi(|0|) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: c#_A(x1) = max{1, x1 - 32} c_A(x1) = max{84, x1 + 28} a_A(x1,x2) = max{59, x2 + 24} b_A(x1,x2) = max{83, x2 + 25} |0|_A = 23 precedence: c# = c = a = b = |0| partial status: pi(c#) = [] pi(c) = [1] pi(a) = [2] pi(b) = [] pi(|0|) = [] The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.