YES We show the termination of the TRS R: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(a(),f(b(),x)) -> f#(a(),f(a(),f(a(),x))) p2: f#(a(),f(b(),x)) -> f#(a(),f(a(),x)) p3: f#(a(),f(b(),x)) -> f#(a(),x) p4: f#(b(),f(a(),x)) -> f#(b(),f(b(),f(b(),x))) p5: f#(b(),f(a(),x)) -> f#(b(),f(b(),x)) p6: f#(b(),f(a(),x)) -> f#(b(),x) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The estimated dependency graph contains the following SCCs: {p1, p2, p3} {p4, p5, p6} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(a(),f(b(),x)) -> f#(a(),f(a(),f(a(),x))) p2: f#(a(),f(b(),x)) -> f#(a(),x) p3: f#(a(),f(b(),x)) -> f#(a(),f(a(),x)) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The set of usable rules consists of r1 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: f#_A(x1,x2) = x2 a_A() = 0 f_A(x1,x2) = x1 + x2 b_A() = 0 precedence: f > b > f# = a partial status: pi(f#) = [2] pi(a) = [] pi(f) = [1, 2] 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: f#(a(),f(b(),x)) -> f#(a(),f(a(),f(a(),x))) p2: f#(a(),f(b(),x)) -> f#(a(),x) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(a(),f(b(),x)) -> f#(a(),f(a(),f(a(),x))) p2: f#(a(),f(b(),x)) -> f#(a(),x) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The set of usable rules consists of r1 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: f#_A(x1,x2) = x2 a_A() = 0 f_A(x1,x2) = x1 + x2 b_A() = 0 precedence: f = b > a > f# partial status: pi(f#) = [2] pi(a) = [] pi(f) = [1, 2] 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: f#(a(),f(b(),x)) -> f#(a(),f(a(),f(a(),x))) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(a(),f(b(),x)) -> f#(a(),f(a(),f(a(),x))) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The set of usable rules consists of r1 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: f#_A(x1,x2) = x2 + 3 a_A() = 1 f_A(x1,x2) = x1 + x2 + 2 b_A() = 8 precedence: b > a = f > f# partial status: pi(f#) = [] pi(a) = [] pi(f) = [1, 2] pi(b) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(b(),f(a(),x)) -> f#(b(),f(b(),f(b(),x))) p2: f#(b(),f(a(),x)) -> f#(b(),x) p3: f#(b(),f(a(),x)) -> f#(b(),f(b(),x)) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The set of usable rules consists of r2 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: f#_A(x1,x2) = x2 b_A() = 0 f_A(x1,x2) = x1 + x2 a_A() = 0 precedence: f > a > f# = b partial status: pi(f#) = [2] pi(b) = [] pi(f) = [1, 2] pi(a) = [] 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: f#(b(),f(a(),x)) -> f#(b(),f(b(),f(b(),x))) p2: f#(b(),f(a(),x)) -> f#(b(),x) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(b(),f(a(),x)) -> f#(b(),f(b(),f(b(),x))) p2: f#(b(),f(a(),x)) -> f#(b(),x) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The set of usable rules consists of r2 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: f#_A(x1,x2) = x2 b_A() = 0 f_A(x1,x2) = x1 + x2 a_A() = 0 precedence: f = a > b > f# partial status: pi(f#) = [2] pi(b) = [] pi(f) = [1, 2] pi(a) = [] 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: f#(b(),f(a(),x)) -> f#(b(),f(b(),f(b(),x))) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(b(),f(a(),x)) -> f#(b(),f(b(),f(b(),x))) and R consists of: r1: f(a(),f(b(),x)) -> f(a(),f(a(),f(a(),x))) r2: f(b(),f(a(),x)) -> f(b(),f(b(),f(b(),x))) The set of usable rules consists of r2 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: f#_A(x1,x2) = x2 + 3 b_A() = 1 f_A(x1,x2) = x1 + x2 + 2 a_A() = 8 precedence: a > b = f > f# partial status: pi(f#) = [] pi(b) = [] pi(f) = [1, 2] pi(a) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.