YES We show the termination of the TRS R: f(s(x),y) -> f(x,s(x)) f(x,s(y)) -> f(y,x) f(c(x),y) -> f(x,s(x)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(s(x),y) -> f#(x,s(x)) p2: f#(x,s(y)) -> f#(y,x) p3: f#(c(x),y) -> f#(x,s(x)) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(x)) The estimated dependency graph contains the following SCCs: {p1, p2, p3} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(s(x),y) -> f#(x,s(x)) p2: f#(c(x),y) -> f#(x,s(x)) p3: f#(x,s(y)) -> f#(y,x) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(x)) The set of usable rules consists of r1, r2, r3 Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: f#_A(x1,x2) = max{x1 + 2, x2 - 3} s_A(x1) = x1 + 6 c_A(x1) = x1 + 6 f_A(x1,x2) = max{1, x1 - 7, x2 - 7} base order 2: precedence: f# > c > s = f partial status: pi(f#) = [1] pi(s) = [] pi(c) = [1] pi(f) = [] The following rules are removed: p1 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(x),y) -> f#(x,s(x)) p2: f#(x,s(y)) -> f#(y,x) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(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#(c(x),y) -> f#(x,s(x)) p2: f#(x,s(y)) -> f#(y,x) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(x)) The set of usable rules consists of r1, r2, r3 Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: f#_A(x1,x2) = max{x1 + 3, x2 + 2} c_A(x1) = x1 + 6 s_A(x1) = x1 + 4 f_A(x1,x2) = max{2, x1 - 7, x2 - 7} base order 2: precedence: c > f# = s = f partial status: pi(f#) = [1] pi(c) = [1] pi(s) = [1] pi(f) = [] The following rules are removed: p2 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(c(x),y) -> f#(x,s(x)) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(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#(c(x),y) -> f#(x,s(x)) and R consists of: r1: f(s(x),y) -> f(x,s(x)) r2: f(x,s(y)) -> f(y,x) r3: f(c(x),y) -> f(x,s(x)) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: f#_A(x1,x2) = max{x1 + 1, x2 + 2} c_A(x1) = max{13, x1 + 8} s_A(x1) = max{10, x1 + 1} base order 2: precedence: c > f# > s partial status: pi(f#) = [1] pi(c) = [1] pi(s) = [1] The following rules are removed: p1 Then no dependency pair remains.