YES We show the termination of the TRS R: app(app(plus(),|0|()),y) -> y app(app(plus(),app(s(),x)),y) -> app(s(),app(app(plus(),x),y)) app(inc(),xs) -> app(app(map(),app(plus(),app(s(),|0|()))),xs) app(app(map(),f),nil()) -> nil() app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) 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(inc_0(),y) -> inc_1(y) app(map_0(),y) -> map_1(y) app(map_1(x1),y) -> map_2(x1,y) app(plus_0(),y) -> plus_1(y) app(plus_1(x1),y) -> plus_2(x1,y) app(s_0(),y) -> s_1(y) plus_2(|0|_0(),y) -> y plus_2(s_1(x),y) -> s_1(plus_2(x,y)) inc_1(xs) -> map_2(plus_1(s_1(|0|_0())),xs) map_2(f,nil_0()) -> nil_0() map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(inc_0(),y) -> inc_1#(y) p2: app#(map_1(x1),y) -> map_2#(x1,y) p3: app#(plus_1(x1),y) -> plus_2#(x1,y) p4: plus_2#(s_1(x),y) -> plus_2#(x,y) p5: inc_1#(xs) -> map_2#(plus_1(s_1(|0|_0())),xs) p6: map_2#(f,cons_2(x,xs)) -> app#(f,x) p7: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(inc_0(),y) -> inc_1(y) r4: app(map_0(),y) -> map_1(y) r5: app(map_1(x1),y) -> map_2(x1,y) r6: app(plus_0(),y) -> plus_1(y) r7: app(plus_1(x1),y) -> plus_2(x1,y) r8: app(s_0(),y) -> s_1(y) r9: plus_2(|0|_0(),y) -> y r10: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r11: inc_1(xs) -> map_2(plus_1(s_1(|0|_0())),xs) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) The estimated dependency graph contains the following SCCs: {p1, p2, p5, p6, p7} {p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(inc_0(),y) -> inc_1#(y) p2: inc_1#(xs) -> map_2#(plus_1(s_1(|0|_0())),xs) p3: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p4: map_2#(f,cons_2(x,xs)) -> app#(f,x) p5: app#(map_1(x1),y) -> map_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(inc_0(),y) -> inc_1(y) r4: app(map_0(),y) -> map_1(y) r5: app(map_1(x1),y) -> map_2(x1,y) r6: app(plus_0(),y) -> plus_1(y) r7: app(plus_1(x1),y) -> plus_2(x1,y) r8: app(s_0(),y) -> s_1(y) r9: plus_2(|0|_0(),y) -> y r10: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r11: inc_1(xs) -> map_2(plus_1(s_1(|0|_0())),xs) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) The set of usable rules consists of r1, r2, r6, r8, r10 Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: app#_A(x1,x2) = max{2, x1} inc_0_A = 8 inc_1#_A(x1) = 8 map_2#_A(x1,x2) = x1 + 3 plus_1_A(x1) = 0 s_1_A(x1) = 9 |0|_0_A = 1 cons_2_A(x1,x2) = max{4, x1 - 20, x2 - 20} map_1_A(x1) = max{10, x1 + 6} app_A(x1,x2) = max{19, x1 - 11, x2 - 7} cons_0_A = 12 cons_1_A(x1) = max{13, x1 - 8} plus_0_A = 10 s_0_A = 10 plus_2_A(x1,x2) = max{10, x2 - 8} base order 2: precedence: inc_0 = app = cons_0 = plus_0 > cons_2 = map_1 = s_0 = plus_2 > app# = s_1 = cons_1 > inc_1# > map_2# = plus_1 = |0|_0 partial status: pi(app#) = [1] pi(inc_0) = [] pi(inc_1#) = [] pi(map_2#) = [1] pi(plus_1) = [] pi(s_1) = [] pi(|0|_0) = [] pi(cons_2) = [] pi(map_1) = [1] pi(app) = [] pi(cons_0) = [] pi(cons_1) = [] pi(plus_0) = [] pi(s_0) = [] pi(plus_2) = [] The following rules are removed: p1 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: inc_1#(xs) -> map_2#(plus_1(s_1(|0|_0())),xs) p2: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p3: map_2#(f,cons_2(x,xs)) -> app#(f,x) p4: app#(map_1(x1),y) -> map_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(inc_0(),y) -> inc_1(y) r4: app(map_0(),y) -> map_1(y) r5: app(map_1(x1),y) -> map_2(x1,y) r6: app(plus_0(),y) -> plus_1(y) r7: app(plus_1(x1),y) -> plus_2(x1,y) r8: app(s_0(),y) -> s_1(y) r9: plus_2(|0|_0(),y) -> y r10: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r11: inc_1(xs) -> map_2(plus_1(s_1(|0|_0())),xs) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) The estimated dependency graph contains the following SCCs: {p2, p3, p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p2: map_2#(f,cons_2(x,xs)) -> app#(f,x) p3: app#(map_1(x1),y) -> map_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(inc_0(),y) -> inc_1(y) r4: app(map_0(),y) -> map_1(y) r5: app(map_1(x1),y) -> map_2(x1,y) r6: app(plus_0(),y) -> plus_1(y) r7: app(plus_1(x1),y) -> plus_2(x1,y) r8: app(s_0(),y) -> s_1(y) r9: plus_2(|0|_0(),y) -> y r10: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r11: inc_1(xs) -> map_2(plus_1(s_1(|0|_0())),xs) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) The set of usable rules consists of r1, r2, r6, r8 Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: map_2#_A(x1,x2) = x1 + 5 cons_2_A(x1,x2) = max{5, x1 - 17, x2 - 17} app#_A(x1,x2) = max{4, x1 + 2} map_1_A(x1) = x1 + 6 app_A(x1,x2) = max{16, x1 - 7, x2 - 8} cons_0_A = 6 cons_1_A(x1) = max{4, x1 - 9} plus_0_A = 5 plus_1_A(x1) = max{6, x1 - 9} s_0_A = 2 s_1_A(x1) = max{3, x1 - 17} base order 2: precedence: app# = map_1 > map_2# = app = cons_0 > cons_2 = plus_1 > cons_1 = plus_0 = s_1 > s_0 partial status: pi(map_2#) = [] pi(cons_2) = [] pi(app#) = [1] pi(map_1) = [1] pi(app) = [] pi(cons_0) = [] pi(cons_1) = [] pi(plus_0) = [] pi(plus_1) = [] pi(s_0) = [] pi(s_1) = [] The following rules are removed: p2 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p2: app#(map_1(x1),y) -> map_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(inc_0(),y) -> inc_1(y) r4: app(map_0(),y) -> map_1(y) r5: app(map_1(x1),y) -> map_2(x1,y) r6: app(plus_0(),y) -> plus_1(y) r7: app(plus_1(x1),y) -> plus_2(x1,y) r8: app(s_0(),y) -> s_1(y) r9: plus_2(|0|_0(),y) -> y r10: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r11: inc_1(xs) -> map_2(plus_1(s_1(|0|_0())),xs) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(inc_0(),y) -> inc_1(y) r4: app(map_0(),y) -> map_1(y) r5: app(map_1(x1),y) -> map_2(x1,y) r6: app(plus_0(),y) -> plus_1(y) r7: app(plus_1(x1),y) -> plus_2(x1,y) r8: app(s_0(),y) -> s_1(y) r9: plus_2(|0|_0(),y) -> y r10: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r11: inc_1(xs) -> map_2(plus_1(s_1(|0|_0())),xs) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) The set of usable rules consists of r1, r4, r8 Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: map_2#_A(x1,x2) = max{x1 + 5, x2 + 13} cons_2_A(x1,x2) = max{3, x1 - 8, x2} app_A(x1,x2) = max{13, x1 - 3, x2 - 7} cons_0_A = 1 cons_1_A(x1) = max{2, x1 - 9} map_0_A = 1 map_1_A(x1) = max{2, x1 - 8} s_0_A = 2 s_1_A(x1) = max{5, x1 - 11} base order 2: precedence: app > map_2# = s_1 > cons_2 = map_1 = s_0 > cons_1 = map_0 > cons_0 partial status: pi(map_2#) = [2] pi(cons_2) = [2] pi(app) = [] pi(cons_0) = [] pi(cons_1) = [] pi(map_0) = [] pi(map_1) = [] pi(s_0) = [] pi(s_1) = [] The following rules are removed: p1 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: plus_2#(s_1(x),y) -> plus_2#(x,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(inc_0(),y) -> inc_1(y) r4: app(map_0(),y) -> map_1(y) r5: app(map_1(x1),y) -> map_2(x1,y) r6: app(plus_0(),y) -> plus_1(y) r7: app(plus_1(x1),y) -> plus_2(x1,y) r8: app(s_0(),y) -> s_1(y) r9: plus_2(|0|_0(),y) -> y r10: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r11: inc_1(xs) -> map_2(plus_1(s_1(|0|_0())),xs) r12: map_2(f,nil_0()) -> nil_0() r13: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) The set of usable rules consists of r1, r4, r6 Take the reduction pair: generalized weighted path order (>=MG, >MG) base order 1: max/plus interpretation on natural numbers: plus_2#_A(x1,x2) = max{x1 + 18, x2 + 19} s_1_A(x1) = x1 + 17 app_A(x1,x2) = max{4, x1 - 8, x2 - 19} cons_0_A = 1 cons_1_A(x1) = max{2, x1 - 20} map_0_A = 2 map_1_A(x1) = max{3, x1 - 20} plus_0_A = 2 plus_1_A(x1) = max{3, x1 - 20} base order 2: precedence: plus_2# > s_1 > app = plus_0 > cons_1 = map_1 = plus_1 > cons_0 = map_0 partial status: pi(plus_2#) = [1] pi(s_1) = [1] pi(app) = [] pi(cons_0) = [] pi(cons_1) = [] pi(map_0) = [] pi(map_1) = [] pi(plus_0) = [] pi(plus_1) = [] The following rules are removed: p1 Then no dependency pair remains.