YES We show the termination of the TRS R: f(X) -> if(X,c(),n__f(true())) if(true(),X,Y) -> X if(false(),X,Y) -> activate(Y) f(X) -> n__f(X) activate(n__f(X)) -> f(X) activate(X) -> X -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: f#(X) -> if#(X,c(),n__f(true())) p2: if#(false(),X,Y) -> activate#(Y) p3: activate#(n__f(X)) -> f#(X) and R consists of: r1: f(X) -> if(X,c(),n__f(true())) r2: if(true(),X,Y) -> X r3: if(false(),X,Y) -> activate(Y) r4: f(X) -> n__f(X) r5: activate(n__f(X)) -> f(X) r6: activate(X) -> 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#(X) -> if#(X,c(),n__f(true())) p2: if#(false(),X,Y) -> activate#(Y) p3: activate#(n__f(X)) -> f#(X) and R consists of: r1: f(X) -> if(X,c(),n__f(true())) r2: if(true(),X,Y) -> X r3: if(false(),X,Y) -> activate(Y) r4: f(X) -> n__f(X) r5: activate(n__f(X)) -> f(X) r6: activate(X) -> 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: f#_A(x1) = max{9, x1 + 5} if#_A(x1,x2,x3) = max{x1 + 4, x2 + 9, x3 - 3} c_A = 0 n__f_A(x1) = x1 + 10 true_A = 1 false_A = 6 activate#_A(x1) = max{9, x1 - 4} precedence: n__f > true = false > activate# > f# > if# = c partial status: pi(f#) = [] pi(if#) = [] pi(c) = [] pi(n__f) = [] pi(true) = [] pi(false) = [] pi(activate#) = [] 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#(X) -> if#(X,c(),n__f(true())) p2: if#(false(),X,Y) -> activate#(Y) and R consists of: r1: f(X) -> if(X,c(),n__f(true())) r2: if(true(),X,Y) -> X r3: if(false(),X,Y) -> activate(Y) r4: f(X) -> n__f(X) r5: activate(n__f(X)) -> f(X) r6: activate(X) -> X The estimated dependency graph contains the following SCCs: (no SCCs)