YES We show the termination of the TRS R: app(app(app(uncurry(),f),x),y) -> app(app(f,x),y) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(app(uncurry(),f),x),y) -> app#(app(f,x),y) p2: app#(app(app(uncurry(),f),x),y) -> app#(f,x) and R consists of: r1: app(app(app(uncurry(),f),x),y) -> app(app(f,x),y) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(app(uncurry(),f),x),y) -> app#(app(f,x),y) p2: app#(app(app(uncurry(),f),x),y) -> app#(f,x) and R consists of: r1: app(app(app(uncurry(),f),x),y) -> app(app(f,x),y) The set of usable rules consists of r1 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: app#_A(x1,x2) = ((0,1),(0,0)) x1 + (2,12) app_A(x1,x2) = ((0,0),(1,1)) x1 + ((0,0),(1,1)) x2 + (5,2) uncurry_A() = (1,1) precedence: app > app# = uncurry partial status: pi(app#) = [] pi(app) = [] pi(uncurry) = [] 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: app#(app(app(uncurry(),f),x),y) -> app#(f,x) and R consists of: r1: app(app(app(uncurry(),f),x),y) -> app(app(f,x),y) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(app(uncurry(),f),x),y) -> app#(f,x) and R consists of: r1: app(app(app(uncurry(),f),x),y) -> app(app(f,x),y) The set of usable rules consists of (no rules) Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^2 order: standard order interpretations: app#_A(x1,x2) = ((1,0),(0,0)) x1 + (1,2) app_A(x1,x2) = ((1,0),(0,0)) x1 + ((1,0),(0,0)) x2 + (1,1) uncurry_A() = (2,1) precedence: app# = app = uncurry partial status: pi(app#) = [] pi(app) = [] pi(uncurry) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.