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(app(app(curry(),f),x),y) -> app(app(f,x),y) add() -> app(curry(),plus()) Instead we prove termination of the uncurried system: app(curry_0(),y) -> curry_1(y) app(curry_1(x1),y) -> curry_2(x1,y) app(curry_2(x1,x2),y) -> curry_3(x1,x2,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)) curry_3(f,x,y) -> app(app(f,x),y) add_0() -> curry_1(plus_0()) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(curry_2(x1,x2),y) -> curry_3#(x1,x2,y) p2: app#(plus_1(x1),y) -> plus_2#(x1,y) p3: plus_2#(s_1(x),y) -> plus_2#(x,y) p4: curry_3#(f,x,y) -> app#(app(f,x),y) p5: curry_3#(f,x,y) -> app#(f,x) and R consists of: r1: app(curry_0(),y) -> curry_1(y) r2: app(curry_1(x1),y) -> curry_2(x1,y) r3: app(curry_2(x1,x2),y) -> curry_3(x1,x2,y) r4: app(plus_0(),y) -> plus_1(y) r5: app(plus_1(x1),y) -> plus_2(x1,y) r6: app(s_0(),y) -> s_1(y) r7: plus_2(|0|_0(),y) -> y r8: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r9: curry_3(f,x,y) -> app(app(f,x),y) r10: add_0() -> curry_1(plus_0()) The estimated dependency graph contains the following SCCs: {p1, p4, p5} {p3} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(curry_2(x1,x2),y) -> curry_3#(x1,x2,y) p2: curry_3#(f,x,y) -> app#(f,x) p3: curry_3#(f,x,y) -> app#(app(f,x),y) and R consists of: r1: app(curry_0(),y) -> curry_1(y) r2: app(curry_1(x1),y) -> curry_2(x1,y) r3: app(curry_2(x1,x2),y) -> curry_3(x1,x2,y) r4: app(plus_0(),y) -> plus_1(y) r5: app(plus_1(x1),y) -> plus_2(x1,y) r6: app(s_0(),y) -> s_1(y) r7: plus_2(|0|_0(),y) -> y r8: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r9: curry_3(f,x,y) -> app(app(f,x),y) r10: add_0() -> curry_1(plus_0()) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: app#_A(x1,x2) = 8 curry_2_A(x1,x2) = max{x1 - 6, x2 + 7} curry_3#_A(x1,x2,x3) = 8 app_A(x1,x2) = max{x1 - 6, x2 + 7} curry_0_A = 1 curry_1_A(x1) = max{2, x1} curry_3_A(x1,x2,x3) = max{x1 - 12, x2 + 1, x3 + 7} plus_0_A = 4 plus_1_A(x1) = max{5, x1 - 1} plus_2_A(x1,x2) = max{3, x1 - 8, x2 + 2} s_0_A = 2 s_1_A(x1) = max{3, x1 - 8} |0|_0_A = 0 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: app#_A(x1,x2) = max{0, x1 - 14, x2 - 8} curry_2_A(x1,x2) = max{x1 + 4, x2 + 13} curry_3#_A(x1,x2,x3) = max{0, x1 - 14, x2 - 1, x3 - 8} app_A(x1,x2) = max{x1 - 9, x2 + 13} curry_0_A = 10 curry_1_A(x1) = x1 + 13 curry_3_A(x1,x2,x3) = max{x1 - 5, x2 + 4, x3 + 13} plus_0_A = 0 plus_1_A(x1) = max{8, x1 - 5} plus_2_A(x1,x2) = max{8, x1 - 14, x2 + 7} s_0_A = 4 s_1_A(x1) = max{8, x1 - 15} |0|_0_A = 0 app#!_A(x1,x2) = max{1, x1 - 1} curry_2!_A(x1,x2) = max{x1 + 8, x2 - 11} curry_3#!_A(x1,x2,x3) = max{x1 + 2, x2 + 12} app!_A(x1,x2) = max{8, x1 - 5, x2 - 10} curry_0!_A = 7 curry_1!_A(x1) = max{6, x1 - 1} curry_3!_A(x1,x2,x3) = max{x1 - 14, x2 + 8, x3 - 10} plus_0!_A = 1 plus_1!_A(x1) = max{2, x1 - 11} plus_2!_A(x1,x2) = max{10, x1 - 9, x2 - 3} s_0!_A = 1 s_1!_A(x1) = max{9, x1 - 10} |0|_0!_A = 0 partial status: pi(app#) = [] pi(curry_2) = [] pi(curry_3#) = [] pi(app) = [] pi(curry_0) = [] pi(curry_1) = [1] pi(curry_3) = [] pi(plus_0) = [] pi(plus_1) = [] pi(plus_2) = [2] pi(s_0) = [] pi(s_1) = [] pi(|0|_0) = [] The following rules are removed: p2 -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(curry_2(x1,x2),y) -> curry_3#(x1,x2,y) p2: curry_3#(f,x,y) -> app#(app(f,x),y) and R consists of: r1: app(curry_0(),y) -> curry_1(y) r2: app(curry_1(x1),y) -> curry_2(x1,y) r3: app(curry_2(x1,x2),y) -> curry_3(x1,x2,y) r4: app(plus_0(),y) -> plus_1(y) r5: app(plus_1(x1),y) -> plus_2(x1,y) r6: app(s_0(),y) -> s_1(y) r7: plus_2(|0|_0(),y) -> y r8: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r9: curry_3(f,x,y) -> app(app(f,x),y) r10: add_0() -> curry_1(plus_0()) 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#(curry_2(x1,x2),y) -> curry_3#(x1,x2,y) p2: curry_3#(f,x,y) -> app#(app(f,x),y) and R consists of: r1: app(curry_0(),y) -> curry_1(y) r2: app(curry_1(x1),y) -> curry_2(x1,y) r3: app(curry_2(x1,x2),y) -> curry_3(x1,x2,y) r4: app(plus_0(),y) -> plus_1(y) r5: app(plus_1(x1),y) -> plus_2(x1,y) r6: app(s_0(),y) -> s_1(y) r7: plus_2(|0|_0(),y) -> y r8: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r9: curry_3(f,x,y) -> app(app(f,x),y) r10: add_0() -> curry_1(plus_0()) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9 Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: app#_A(x1,x2) = max{1, x1} curry_2_A(x1,x2) = max{x1 + 8, x2 + 16} curry_3#_A(x1,x2,x3) = max{x1 + 5, x2 + 16} app_A(x1,x2) = max{x1 - 7, x2 + 16} curry_0_A = 1 curry_1_A(x1) = x1 + 15 curry_3_A(x1,x2,x3) = max{x1 + 1, x2 + 9, x3 + 16} plus_0_A = 25 plus_1_A(x1) = max{17, x1 - 1} plus_2_A(x1,x2) = max{3, x1 - 9, x2 + 1} s_0_A = 10 s_1_A(x1) = max{2, x1 - 4} |0|_0_A = 0 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: app#_A(x1,x2) = max{1, x1 - 12, x2 - 2} curry_2_A(x1,x2) = max{11, x2 + 7} curry_3#_A(x1,x2,x3) = max{1, x2 - 5, x3 - 2} app_A(x1,x2) = max{11, x2 + 7} curry_0_A = 6 curry_1_A(x1) = max{11, x1 + 7} curry_3_A(x1,x2,x3) = max{11, x3 + 7} plus_0_A = 4 plus_1_A(x1) = 8 plus_2_A(x1,x2) = max{8, x2 + 1} s_0_A = 4 s_1_A(x1) = max{8, x1 - 7} |0|_0_A = 0 app#!_A(x1,x2) = 1 curry_2!_A(x1,x2) = max{7, x1 + 3} curry_3#!_A(x1,x2,x3) = max{6, x1 + 2} app!_A(x1,x2) = max{5, x1 - 3} curry_0!_A = 1 curry_1!_A(x1) = 2 curry_3!_A(x1,x2,x3) = max{8, x2 + 4} plus_0!_A = 1 plus_1!_A(x1) = max{6, x1 - 10} plus_2!_A(x1,x2) = max{0, x1 - 9, x2 - 1} s_0!_A = 1 s_1!_A(x1) = 0 |0|_0!_A = 0 partial status: pi(app#) = [1] pi(curry_2) = [] pi(curry_3#) = [] pi(app) = [] pi(curry_0) = [] pi(curry_1) = [1] pi(curry_3) = [] pi(plus_0) = [] pi(plus_1) = [] pi(plus_2) = [2] pi(s_0) = [] pi(s_1) = [] pi(|0|_0) = [] The following rules are removed: p1, p2 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(curry_0(),y) -> curry_1(y) r2: app(curry_1(x1),y) -> curry_2(x1,y) r3: app(curry_2(x1,x2),y) -> curry_3(x1,x2,y) r4: app(plus_0(),y) -> plus_1(y) r5: app(plus_1(x1),y) -> plus_2(x1,y) r6: app(s_0(),y) -> s_1(y) r7: plus_2(|0|_0(),y) -> y r8: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r9: curry_3(f,x,y) -> app(app(f,x),y) r10: add_0() -> curry_1(plus_0()) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: max/plus interpretation on natural numbers: plus_2#_A(x1,x2) = x1 + 5 s_1_A(x1) = x1 + 6 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: plus_2#_A(x1,x2) = 0 s_1_A(x1) = max{3, x1 - 3} plus_2#!_A(x1,x2) = max{0, x1 - 4} s_1!_A(x1) = max{0, x1 - 3} partial status: pi(plus_2#) = [1] pi(s_1) = [1] The following rules are removed: p1 Then no dependency pair remains.