YES We show the termination of the TRS R: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: plus#(s(X),plus(Y,Z)) -> plus#(X,plus(s(s(Y)),Z)) p2: plus#(s(X),plus(Y,Z)) -> plus#(s(s(Y)),Z) p3: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) p4: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X3,plus(X2,X4)) p5: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X2,X4) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4, p5} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: plus#(s(X),plus(Y,Z)) -> plus#(X,plus(s(s(Y)),Z)) p2: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X2,X4) p3: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X3,plus(X2,X4)) p4: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) p5: plus#(s(X),plus(Y,Z)) -> plus#(s(s(Y)),Z) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The set of usable rules consists of r1, r2 Take the reduction pair: weighted path order base order: max/plus interpretations on natural numbers: plus#_A(x1,x2) = x2 + 22 s_A(x1) = max{44, x1 + 5} plus_A(x1,x2) = x2 + 11 precedence: plus# = plus > s partial status: pi(plus#) = [] pi(s) = [1] pi(plus) = [] 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: plus#(s(X),plus(Y,Z)) -> plus#(X,plus(s(s(Y)),Z)) p2: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X3,plus(X2,X4)) p3: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) p4: plus#(s(X),plus(Y,Z)) -> plus#(s(s(Y)),Z) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: plus#(s(X),plus(Y,Z)) -> plus#(X,plus(s(s(Y)),Z)) p2: plus#(s(X),plus(Y,Z)) -> plus#(s(s(Y)),Z) p3: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) p4: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X3,plus(X2,X4)) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The set of usable rules consists of r1, r2 Take the reduction pair: weighted path order base order: max/plus interpretations on natural numbers: plus#_A(x1,x2) = max{0, x2 - 1} s_A(x1) = max{33, x1 + 4} plus_A(x1,x2) = x2 + 16 precedence: s = plus > plus# partial status: pi(plus#) = [] pi(s) = [1] pi(plus) = [] The next rules are strictly ordered: p4 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: plus#(s(X),plus(Y,Z)) -> plus#(X,plus(s(s(Y)),Z)) p2: plus#(s(X),plus(Y,Z)) -> plus#(s(s(Y)),Z) p3: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) 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: plus#(s(X),plus(Y,Z)) -> plus#(X,plus(s(s(Y)),Z)) p2: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) p3: plus#(s(X),plus(Y,Z)) -> plus#(s(s(Y)),Z) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The set of usable rules consists of r1, r2 Take the reduction pair: weighted path order base order: max/plus interpretations on natural numbers: plus#_A(x1,x2) = x2 + 7 s_A(x1) = 18 plus_A(x1,x2) = x2 + 7 precedence: plus > plus# > s partial status: pi(plus#) = [] pi(s) = [] pi(plus) = [] 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: plus#(s(X),plus(Y,Z)) -> plus#(X,plus(s(s(Y)),Z)) p2: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: plus#(s(X),plus(Y,Z)) -> plus#(X,plus(s(s(Y)),Z)) p2: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The set of usable rules consists of r1, r2 Take the reduction pair: weighted path order base order: max/plus interpretations on natural numbers: plus#_A(x1,x2) = max{x1 + 38, x2 + 26} s_A(x1) = max{16, x1 + 4} plus_A(x1,x2) = 1 precedence: plus# = s = plus partial status: pi(plus#) = [] pi(s) = [1] pi(plus) = [] The next rules are strictly ordered: p1 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: plus#(s(X1),plus(X2,plus(X3,X4))) -> plus#(X1,plus(X3,plus(X2,X4))) and R consists of: r1: plus(s(X),plus(Y,Z)) -> plus(X,plus(s(s(Y)),Z)) r2: plus(s(X1),plus(X2,plus(X3,X4))) -> plus(X1,plus(X3,plus(X2,X4))) The set of usable rules consists of r1, r2 Take the reduction pair: weighted path order base order: max/plus interpretations on natural numbers: plus#_A(x1,x2) = max{0, x1 - 3, x2 - 23} s_A(x1) = x1 + 5 plus_A(x1,x2) = 3 precedence: plus# = s = plus partial status: pi(plus#) = [] pi(s) = [1] pi(plus) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.