YES We show the termination of the TRS R: app(app(fmap(),fnil()),x) -> nil() app(app(fmap(),app(app(fcons(),f),t)),x) -> app(app(cons(),app(f,x)),app(app(fmap(),t),x)) Instead we prove termination of the uncurried system: app(cons_0(),y) -> cons_1(y) app(cons_1(x1),y) -> cons_2(x1,y) app(fcons_0(),y) -> fcons_1(y) app(fcons_1(x1),y) -> fcons_2(x1,y) app(fmap_0(),y) -> fmap_1(y) app(fmap_1(x1),y) -> fmap_2(x1,y) fmap_2(fnil_0(),x) -> nil_0() fmap_2(fcons_2(f,t),x) -> cons_2(app(f,x),fmap_2(t,x)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(fmap_1(x1),y) -> fmap_2#(x1,y) p2: fmap_2#(fcons_2(f,t),x) -> app#(f,x) p3: fmap_2#(fcons_2(f,t),x) -> fmap_2#(t,x) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(fcons_0(),y) -> fcons_1(y) r4: app(fcons_1(x1),y) -> fcons_2(x1,y) r5: app(fmap_0(),y) -> fmap_1(y) r6: app(fmap_1(x1),y) -> fmap_2(x1,y) r7: fmap_2(fnil_0(),x) -> nil_0() r8: fmap_2(fcons_2(f,t),x) -> cons_2(app(f,x),fmap_2(t,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: app#(fmap_1(x1),y) -> fmap_2#(x1,y) p2: fmap_2#(fcons_2(f,t),x) -> fmap_2#(t,x) p3: fmap_2#(fcons_2(f,t),x) -> app#(f,x) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(fcons_0(),y) -> fcons_1(y) r4: app(fcons_1(x1),y) -> fcons_2(x1,y) r5: app(fmap_0(),y) -> fmap_1(y) r6: app(fmap_1(x1),y) -> fmap_2(x1,y) r7: fmap_2(fnil_0(),x) -> nil_0() r8: fmap_2(fcons_2(f,t),x) -> cons_2(app(f,x),fmap_2(t,x)) The set of usable rules consists of r1, r2, r3, r5 Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: app#_A(x1,x2) = x1 + 5 fmap_1_A(x1) = max{3, x1 - 2} fmap_2#_A(x1,x2) = max{2, x1 - 3} fcons_2_A(x1,x2) = max{x1 + 9, x2 + 1} app_A(x1,x2) = max{12, x1 - 12, x2 - 1} cons_0_A = 10 cons_1_A(x1) = max{11, x1 - 2} cons_2_A(x1,x2) = max{10, x1 - 26} fcons_0_A = 5 fcons_1_A(x1) = max{6, x1 - 2} fmap_0_A = 2 base order 2: precedence: app = cons_0 > cons_1 = fcons_0 > app# = fmap_1 = cons_2 > fcons_2 = fmap_0 > fmap_2# = fcons_1 partial status: pi(app#) = [1] pi(fmap_1) = [] pi(fmap_2#) = [] pi(fcons_2) = [] pi(app) = [] pi(cons_0) = [] pi(cons_1) = [] pi(cons_2) = [] pi(fcons_0) = [] pi(fcons_1) = [] pi(fmap_0) = [] The following rules are removed: p2 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(fmap_1(x1),y) -> fmap_2#(x1,y) p2: fmap_2#(fcons_2(f,t),x) -> app#(f,x) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(fcons_0(),y) -> fcons_1(y) r4: app(fcons_1(x1),y) -> fcons_2(x1,y) r5: app(fmap_0(),y) -> fmap_1(y) r6: app(fmap_1(x1),y) -> fmap_2(x1,y) r7: fmap_2(fnil_0(),x) -> nil_0() r8: fmap_2(fcons_2(f,t),x) -> cons_2(app(f,x),fmap_2(t,x)) 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#(fmap_1(x1),y) -> fmap_2#(x1,y) p2: fmap_2#(fcons_2(f,t),x) -> app#(f,x) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(fcons_0(),y) -> fcons_1(y) r4: app(fcons_1(x1),y) -> fcons_2(x1,y) r5: app(fmap_0(),y) -> fmap_1(y) r6: app(fmap_1(x1),y) -> fmap_2(x1,y) r7: fmap_2(fnil_0(),x) -> nil_0() r8: fmap_2(fcons_2(f,t),x) -> cons_2(app(f,x),fmap_2(t,x)) The set of usable rules consists of r1, r2, r3, r5 Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: app#_A(x1,x2) = max{6, x1 - 2} fmap_1_A(x1) = max{10, x1 - 3} fmap_2#_A(x1,x2) = max{7, x1 - 6} fcons_2_A(x1,x2) = max{x1 + 5, x2 - 22} app_A(x1,x2) = max{18, x1 - 11, x2 - 2} cons_0_A = 10 cons_1_A(x1) = max{18, x1 - 2} cons_2_A(x1,x2) = max{6, x1 - 41, x2 - 42} fcons_0_A = 9 fcons_1_A(x1) = max{10, x1 - 3} fmap_0_A = 9 base order 2: precedence: fcons_1 > app = fcons_0 > app# = fmap_1 = cons_2 > fmap_2# = fcons_2 = cons_1 = fmap_0 > cons_0 partial status: pi(app#) = [] pi(fmap_1) = [] pi(fmap_2#) = [] pi(fcons_2) = [1] pi(app) = [] pi(cons_0) = [] pi(cons_1) = [] pi(cons_2) = [] pi(fcons_0) = [] pi(fcons_1) = [] pi(fmap_0) = [] The following rules are removed: p2 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(fmap_1(x1),y) -> fmap_2#(x1,y) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(fcons_0(),y) -> fcons_1(y) r4: app(fcons_1(x1),y) -> fcons_2(x1,y) r5: app(fmap_0(),y) -> fmap_1(y) r6: app(fmap_1(x1),y) -> fmap_2(x1,y) r7: fmap_2(fnil_0(),x) -> nil_0() r8: fmap_2(fcons_2(f,t),x) -> cons_2(app(f,x),fmap_2(t,x)) The estimated dependency graph contains the following SCCs: (no SCCs)