YES We show the termination of the TRS R: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) times(X,s(Y)) -> plus(X,times(Y,X)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: plus#(plus(X,Y),Z) -> plus#(X,plus(Y,Z)) p2: plus#(plus(X,Y),Z) -> plus#(Y,Z) p3: times#(X,s(Y)) -> plus#(X,times(Y,X)) p4: times#(X,s(Y)) -> times#(Y,X) and R consists of: r1: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) r2: times(X,s(Y)) -> plus(X,times(Y,X)) The estimated dependency graph contains the following SCCs: {p4} {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: times#(X,s(Y)) -> times#(Y,X) and R consists of: r1: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) r2: times(X,s(Y)) -> plus(X,times(Y,X)) The set of usable rules consists of (no rules) Take the reduction pair: weighted path order base order: max/plus interpretations on natural numbers: times#_A(x1,x2) = max{x1 + 1, x2 - 1} s_A(x1) = x1 + 3 precedence: times# = s partial status: pi(times#) = [] pi(s) = [1] 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: plus#(plus(X,Y),Z) -> plus#(X,plus(Y,Z)) p2: plus#(plus(X,Y),Z) -> plus#(Y,Z) and R consists of: r1: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) r2: times(X,s(Y)) -> plus(X,times(Y,X)) The set of usable rules consists of r1 Take the monotone reduction pair: weighted path order base order: max/plus interpretations on natural numbers: plus#_A(x1,x2) = max{x1 + 4, x2 + 2} plus_A(x1,x2) = max{x1 + 2, x2} precedence: plus# = plus partial status: pi(plus#) = [1, 2] pi(plus) = [1, 2] 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#(plus(X,Y),Z) -> plus#(Y,Z) and R consists of: r1: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) r2: times(X,s(Y)) -> plus(X,times(Y,X)) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: plus#(plus(X,Y),Z) -> plus#(Y,Z) and R consists of: r1: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) r2: times(X,s(Y)) -> plus(X,times(Y,X)) The set of usable rules consists of (no rules) Take the reduction pair: weighted path order base order: max/plus interpretations on natural numbers: plus#_A(x1,x2) = max{x1 + 1, x2 + 1} plus_A(x1,x2) = x2 precedence: plus# = plus partial status: pi(plus#) = [1] pi(plus) = [2] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.