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: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: a#_A(x1,x2) = max{x1 + 7, x2 + 18} c#_A(x1) = x1 + 13 b_A(x1,x2) = max{36, x1} c_A(x1) = 22 |0|_A = 0 a_A(x1,x2) = x1 + 36 precedence: a > b = c > a# > c# = |0| partial status: pi(a#) = [1, 2] pi(c#) = [] pi(b) = [1] pi(c) = [] pi(|0|) = [] pi(a) = [1] 2. weighted path order base order: max/plus interpretations on natural numbers: a#_A(x1,x2) = max{x1 + 150, x2 + 33} c#_A(x1) = 0 b_A(x1,x2) = max{47, x1 + 6} c_A(x1) = 71 |0|_A = 10 a_A(x1,x2) = max{60, x1 + 9} precedence: c > a > b > |0| > a# = c# partial status: pi(a#) = [2] pi(c#) = [] pi(b) = [1] pi(c) = [] pi(|0|) = [] pi(a) = [] The next rules are strictly ordered: p1, 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)) 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 estimated dependency graph contains the following SCCs: {p1, p2} -- 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: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: c#_A(x1) = x1 + 24 b_A(x1,x2) = max{8, x1, x2 - 2} c_A(x1) = max{4, x1 - 11} a_A(x1,x2) = max{x1 + 8, x2 - 12} |0|_A = 0 precedence: a > b = c > c# = |0| partial status: pi(c#) = [] pi(b) = [1] pi(c) = [] pi(a) = [1] pi(|0|) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: c#_A(x1) = 4 b_A(x1,x2) = 47 c_A(x1) = 54 a_A(x1,x2) = 47 |0|_A = 20 precedence: b = c = a > c# = |0| partial status: pi(c#) = [] pi(b) = [] pi(c) = [] pi(a) = [] 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#(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: lexicographic combination of reduction pairs: 1. weighted path order base order: max/plus interpretations on natural numbers: c#_A(x1) = max{35, x1 + 22} b_A(x1,x2) = max{34, x1 + 16, x2 - 75} c_A(x1) = 168 a_A(x1,x2) = max{x1 + 38, x2 - 62} |0|_A = 37 precedence: c# > a > b = c = |0| partial status: pi(c#) = [1] pi(b) = [] pi(c) = [] pi(a) = [1] pi(|0|) = [] 2. weighted path order base order: max/plus interpretations on natural numbers: c#_A(x1) = 12 b_A(x1,x2) = 14 c_A(x1) = 16 a_A(x1,x2) = x1 + 24 |0|_A = 7 precedence: a = |0| > c# = b = c partial status: pi(c#) = [] pi(b) = [] pi(c) = [] pi(a) = [1] pi(|0|) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.