YES We show the termination of the TRS R: a(x,y) -> b(x,b(|0|(),c(y))) c(b(y,c(x))) -> c(c(b(a(|0|(),|0|()),y))) b(y,|0|()) -> y -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: a#(x,y) -> b#(x,b(|0|(),c(y))) p2: a#(x,y) -> b#(|0|(),c(y)) p3: a#(x,y) -> c#(y) p4: c#(b(y,c(x))) -> c#(c(b(a(|0|(),|0|()),y))) p5: c#(b(y,c(x))) -> c#(b(a(|0|(),|0|()),y)) p6: c#(b(y,c(x))) -> b#(a(|0|(),|0|()),y) p7: c#(b(y,c(x))) -> a#(|0|(),|0|()) and R consists of: r1: a(x,y) -> b(x,b(|0|(),c(y))) r2: c(b(y,c(x))) -> c(c(b(a(|0|(),|0|()),y))) r3: b(y,|0|()) -> y The estimated dependency graph contains the following SCCs: {p3, p4, p5, p7} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: a#(x,y) -> c#(y) p2: c#(b(y,c(x))) -> a#(|0|(),|0|()) p3: c#(b(y,c(x))) -> c#(b(a(|0|(),|0|()),y)) p4: c#(b(y,c(x))) -> c#(c(b(a(|0|(),|0|()),y))) and R consists of: r1: a(x,y) -> b(x,b(|0|(),c(y))) r2: c(b(y,c(x))) -> c(c(b(a(|0|(),|0|()),y))) r3: b(y,|0|()) -> y The set of usable rules consists of r1, r2, r3 Take the reduction pair: max/plus interpretations on natural numbers: a#_A(x1,x2) = max{x1 + 7, x2 + 8} c#_A(x1) = x1 + 8 b_A(x1,x2) = max{4, x1, x2 - 1} c_A(x1) = 4 |0|_A = 0 a_A(x1,x2) = max{x1 + 4, x2 - 7} 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: a#(x,y) -> c#(y) p2: c#(b(y,c(x))) -> c#(b(a(|0|(),|0|()),y)) p3: c#(b(y,c(x))) -> c#(c(b(a(|0|(),|0|()),y))) and R consists of: r1: a(x,y) -> b(x,b(|0|(),c(y))) r2: c(b(y,c(x))) -> c(c(b(a(|0|(),|0|()),y))) r3: b(y,|0|()) -> y The estimated dependency graph contains the following SCCs: {p2, p3} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: c#(b(y,c(x))) -> c#(b(a(|0|(),|0|()),y)) p2: c#(b(y,c(x))) -> c#(c(b(a(|0|(),|0|()),y))) and R consists of: r1: a(x,y) -> b(x,b(|0|(),c(y))) r2: c(b(y,c(x))) -> c(c(b(a(|0|(),|0|()),y))) r3: b(y,|0|()) -> y The set of usable rules consists of r1, r2, r3 Take the reduction pair: max/plus interpretations on natural numbers: c#_A(x1) = x1 + 1 b_A(x1,x2) = max{8, x1, x2 - 2} c_A(x1) = 6 a_A(x1,x2) = max{x1 + 1, x2 + 8} |0|_A = 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#(b(y,c(x))) -> c#(b(a(|0|(),|0|()),y)) and R consists of: r1: a(x,y) -> b(x,b(|0|(),c(y))) r2: c(b(y,c(x))) -> c(c(b(a(|0|(),|0|()),y))) r3: b(y,|0|()) -> 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#(b(y,c(x))) -> c#(b(a(|0|(),|0|()),y)) and R consists of: r1: a(x,y) -> b(x,b(|0|(),c(y))) r2: c(b(y,c(x))) -> c(c(b(a(|0|(),|0|()),y))) r3: b(y,|0|()) -> y The set of usable rules consists of r1, r2, r3 Take the reduction pair: max/plus interpretations on natural numbers: c#_A(x1) = x1 + 3 b_A(x1,x2) = max{4, x1, x2 - 2} c_A(x1) = max{8, x1} a_A(x1,x2) = max{5, x1 + 1, x2 - 4} |0|_A = 0 The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.