YES We show the termination of the TRS R: f(x,c(y)) -> f(x,s(f(y,y))) f(s(x),y) -> f(x,s(c(y))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(x,c(y)) -> f#(x,s(f(y,y))) p2: f#(x,c(y)) -> f#(y,y) p3: f#(s(x),y) -> f#(x,s(c(y))) and R consists of: r1: f(x,c(y)) -> f(x,s(f(y,y))) r2: f(s(x),y) -> f(x,s(c(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: f#(x,c(y)) -> f#(y,y) and R consists of: r1: f(x,c(y)) -> f(x,s(f(y,y))) r2: f(s(x),y) -> f(x,s(c(y))) The set of usable rules consists of r1, r2 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: model-based reduction triple (=A, >=A!, >A!): finite algebra: carrier: {0,1} interpretations: f#_A(0,0) = 0 f#_A(0,1) = 0 f#_A(1,0) = 0 f#_A(1,1) = 0 c_A(0) = 1 c_A(1) = 0 f_A(0,0) = 0 f_A(0,1) = 0 f_A(1,0) = 0 f_A(1,1) = 0 s_A(0) = 1 s_A(1) = 1 f#!_A(0,0) = 0 f#!_A(0,1) = 0 f#!_A(1,0) = 0 f#!_A(1,1) = 0 c!_A(0) = 1 c!_A(1) = 1 f!_A(0,0) = 0 f!_A(0,1) = 0 f!_A(1,0) = 0 f!_A(1,1) = 0 s!_A(0) = 0 s!_A(1) = 1 partial status: pi(f#) = [2] pi(c) = [1] pi(f) = [1] pi(s) = [1] The following rules are removed: p1 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: f#(s(x),y) -> f#(x,s(c(y))) and R consists of: r1: f(x,c(y)) -> f(x,s(f(y,y))) r2: f(s(x),y) -> f(x,s(c(y))) The set of usable rules consists of r1, r2 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: trivial reduction triple (T x T, T x T, Φ) base order 2: model-based reduction triple (=A, >=A!, >A!): finite algebra: carrier: {0,1} interpretations: f#_A(0,0) = 0 f#_A(0,1) = 0 f#_A(1,0) = 0 f#_A(1,1) = 0 s_A(0) = 1 s_A(1) = 0 c_A(0) = 0 c_A(1) = 0 f_A(0,0) = 0 f_A(0,1) = 0 f_A(1,0) = 0 f_A(1,1) = 0 f#!_A(0,0) = 1 f#!_A(0,1) = 0 f#!_A(1,0) = 0 f#!_A(1,1) = 0 s!_A(0) = 1 s!_A(1) = 1 c!_A(0) = 0 c!_A(1) = 0 f!_A(0,0) = 0 f!_A(0,1) = 0 f!_A(1,0) = 0 f!_A(1,1) = 0 partial status: pi(f#) = [1] pi(s) = [1] pi(c) = [] pi(f) = [] The following rules are removed: p1 Then no dependency pair remains.