YES We show the termination of the TRS R: fst(|0|(),Z) -> nil() fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z))) from(X) -> cons(X,n__from(n__s(X))) add(|0|(),X) -> X add(s(X),Y) -> s(n__add(activate(X),Y)) len(nil()) -> |0|() len(cons(X,Z)) -> s(n__len(activate(Z))) fst(X1,X2) -> n__fst(X1,X2) from(X) -> n__from(X) s(X) -> n__s(X) add(X1,X2) -> n__add(X1,X2) len(X) -> n__len(X) activate(n__fst(X1,X2)) -> fst(activate(X1),activate(X2)) activate(n__from(X)) -> from(activate(X)) activate(n__s(X)) -> s(X) activate(n__add(X1,X2)) -> add(activate(X1),activate(X2)) activate(n__len(X)) -> len(activate(X)) activate(X) -> X -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: fst#(s(X),cons(Y,Z)) -> activate#(X) p2: fst#(s(X),cons(Y,Z)) -> activate#(Z) p3: add#(s(X),Y) -> s#(n__add(activate(X),Y)) p4: add#(s(X),Y) -> activate#(X) p5: len#(cons(X,Z)) -> s#(n__len(activate(Z))) p6: len#(cons(X,Z)) -> activate#(Z) p7: activate#(n__fst(X1,X2)) -> fst#(activate(X1),activate(X2)) p8: activate#(n__fst(X1,X2)) -> activate#(X1) p9: activate#(n__fst(X1,X2)) -> activate#(X2) p10: activate#(n__from(X)) -> from#(activate(X)) p11: activate#(n__from(X)) -> activate#(X) p12: activate#(n__s(X)) -> s#(X) p13: activate#(n__add(X1,X2)) -> add#(activate(X1),activate(X2)) p14: activate#(n__add(X1,X2)) -> activate#(X1) p15: activate#(n__add(X1,X2)) -> activate#(X2) p16: activate#(n__len(X)) -> len#(activate(X)) p17: activate#(n__len(X)) -> activate#(X) and R consists of: r1: fst(|0|(),Z) -> nil() r2: fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z))) r3: from(X) -> cons(X,n__from(n__s(X))) r4: add(|0|(),X) -> X r5: add(s(X),Y) -> s(n__add(activate(X),Y)) r6: len(nil()) -> |0|() r7: len(cons(X,Z)) -> s(n__len(activate(Z))) r8: fst(X1,X2) -> n__fst(X1,X2) r9: from(X) -> n__from(X) r10: s(X) -> n__s(X) r11: add(X1,X2) -> n__add(X1,X2) r12: len(X) -> n__len(X) r13: activate(n__fst(X1,X2)) -> fst(activate(X1),activate(X2)) r14: activate(n__from(X)) -> from(activate(X)) r15: activate(n__s(X)) -> s(X) r16: activate(n__add(X1,X2)) -> add(activate(X1),activate(X2)) r17: activate(n__len(X)) -> len(activate(X)) r18: activate(X) -> X The estimated dependency graph contains the following SCCs: {p1, p2, p4, p6, p7, p8, p9, p11, p13, p14, p15, p16, p17} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: fst#(s(X),cons(Y,Z)) -> activate#(X) p2: activate#(n__len(X)) -> activate#(X) p3: activate#(n__len(X)) -> len#(activate(X)) p4: len#(cons(X,Z)) -> activate#(Z) p5: activate#(n__add(X1,X2)) -> activate#(X2) p6: activate#(n__add(X1,X2)) -> activate#(X1) p7: activate#(n__add(X1,X2)) -> add#(activate(X1),activate(X2)) p8: add#(s(X),Y) -> activate#(X) p9: activate#(n__from(X)) -> activate#(X) p10: activate#(n__fst(X1,X2)) -> activate#(X2) p11: activate#(n__fst(X1,X2)) -> activate#(X1) p12: activate#(n__fst(X1,X2)) -> fst#(activate(X1),activate(X2)) p13: fst#(s(X),cons(Y,Z)) -> activate#(Z) and R consists of: r1: fst(|0|(),Z) -> nil() r2: fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z))) r3: from(X) -> cons(X,n__from(n__s(X))) r4: add(|0|(),X) -> X r5: add(s(X),Y) -> s(n__add(activate(X),Y)) r6: len(nil()) -> |0|() r7: len(cons(X,Z)) -> s(n__len(activate(Z))) r8: fst(X1,X2) -> n__fst(X1,X2) r9: from(X) -> n__from(X) r10: s(X) -> n__s(X) r11: add(X1,X2) -> n__add(X1,X2) r12: len(X) -> n__len(X) r13: activate(n__fst(X1,X2)) -> fst(activate(X1),activate(X2)) r14: activate(n__from(X)) -> from(activate(X)) r15: activate(n__s(X)) -> s(X) r16: activate(n__add(X1,X2)) -> add(activate(X1),activate(X2)) r17: activate(n__len(X)) -> len(activate(X)) r18: activate(X) -> X The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, r16, r17, r18 Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: fst#_A(x1,x2) = ((1,0),(0,0)) x1 + x2 + (3,4) s_A(x1) = ((1,0),(0,0)) x1 + (0,4) cons_A(x1,x2) = ((1,0),(0,0)) x2 + (0,1) activate#_A(x1) = ((1,0),(1,1)) x1 + (2,13) n__len_A(x1) = ((1,0),(0,0)) x1 + (4,5) len#_A(x1) = x1 + (3,11) activate_A(x1) = x1 + (0,11) n__add_A(x1,x2) = x1 + ((1,0),(0,0)) x2 + (4,12) add#_A(x1,x2) = ((1,0),(0,0)) x1 + ((0,0),(1,0)) x2 + (3,11) n__from_A(x1) = ((1,0),(1,0)) x1 + (3,2) n__fst_A(x1,x2) = ((1,0),(0,0)) x1 + ((1,0),(0,0)) x2 + (2,14) fst_A(x1,x2) = ((1,0),(0,0)) x1 + ((1,0),(0,0)) x2 + (2,15) |0|_A() = (1,1) nil_A() = (0,2) from_A(x1) = ((1,0),(1,0)) x1 + (3,2) n__s_A(x1) = ((1,0),(0,0)) x1 + (0,3) add_A(x1,x2) = x1 + ((1,0),(0,0)) x2 + (4,12) len_A(x1) = ((1,0),(0,0)) x1 + (4,5) precedence: add# > |0| > nil > activate = fst = from = add = len > s = n__add > fst# = activate# = len# = n__from = n__s > n__fst > cons = n__len partial status: pi(fst#) = [2] pi(s) = [] pi(cons) = [] pi(activate#) = [1] pi(n__len) = [] pi(len#) = [1] pi(activate) = [1] pi(n__add) = [1] pi(add#) = [] pi(n__from) = [] pi(n__fst) = [] pi(fst) = [] pi(|0|) = [] pi(nil) = [] pi(from) = [] pi(n__s) = [] pi(add) = [1] pi(len) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: fst#_A(x1,x2) = x2 + (1,0) s_A(x1) = (5,0) cons_A(x1,x2) = (4,8) activate#_A(x1) = (4,4) n__len_A(x1) = (5,5) len#_A(x1) = ((1,0),(1,0)) x1 activate_A(x1) = ((1,0),(1,0)) x1 + (2,2) n__add_A(x1,x2) = ((1,0),(0,0)) x1 add#_A(x1,x2) = (5,5) n__from_A(x1) = (5,7) n__fst_A(x1,x2) = (6,0) fst_A(x1,x2) = (7,7) |0|_A() = (0,0) nil_A() = (0,0) from_A(x1) = (8,8) n__s_A(x1) = (0,0) add_A(x1,x2) = ((1,0),(0,0)) x1 + (0,1) len_A(x1) = (7,6) precedence: cons = activate = add > len > fst# = s = activate# = len# = add# = n__fst > n__len > n__add > from > |0| > fst = nil > n__from = n__s partial status: pi(fst#) = [] pi(s) = [] pi(cons) = [] pi(activate#) = [] pi(n__len) = [] pi(len#) = [] pi(activate) = [] pi(n__add) = [] pi(add#) = [] pi(n__from) = [] pi(n__fst) = [] pi(fst) = [] pi(|0|) = [] pi(nil) = [] pi(from) = [] pi(n__s) = [] pi(add) = [] pi(len) = [] The next rules are strictly ordered: p3, p7, p8, p10, p12 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: fst#(s(X),cons(Y,Z)) -> activate#(X) p2: activate#(n__len(X)) -> activate#(X) p3: len#(cons(X,Z)) -> activate#(Z) p4: activate#(n__add(X1,X2)) -> activate#(X2) p5: activate#(n__add(X1,X2)) -> activate#(X1) p6: activate#(n__from(X)) -> activate#(X) p7: activate#(n__fst(X1,X2)) -> activate#(X1) p8: fst#(s(X),cons(Y,Z)) -> activate#(Z) and R consists of: r1: fst(|0|(),Z) -> nil() r2: fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z))) r3: from(X) -> cons(X,n__from(n__s(X))) r4: add(|0|(),X) -> X r5: add(s(X),Y) -> s(n__add(activate(X),Y)) r6: len(nil()) -> |0|() r7: len(cons(X,Z)) -> s(n__len(activate(Z))) r8: fst(X1,X2) -> n__fst(X1,X2) r9: from(X) -> n__from(X) r10: s(X) -> n__s(X) r11: add(X1,X2) -> n__add(X1,X2) r12: len(X) -> n__len(X) r13: activate(n__fst(X1,X2)) -> fst(activate(X1),activate(X2)) r14: activate(n__from(X)) -> from(activate(X)) r15: activate(n__s(X)) -> s(X) r16: activate(n__add(X1,X2)) -> add(activate(X1),activate(X2)) r17: activate(n__len(X)) -> len(activate(X)) r18: activate(X) -> X The estimated dependency graph contains the following SCCs: {p2, p4, p5, p6, p7} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: activate#(n__len(X)) -> activate#(X) p2: activate#(n__fst(X1,X2)) -> activate#(X1) p3: activate#(n__from(X)) -> activate#(X) p4: activate#(n__add(X1,X2)) -> activate#(X1) p5: activate#(n__add(X1,X2)) -> activate#(X2) and R consists of: r1: fst(|0|(),Z) -> nil() r2: fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z))) r3: from(X) -> cons(X,n__from(n__s(X))) r4: add(|0|(),X) -> X r5: add(s(X),Y) -> s(n__add(activate(X),Y)) r6: len(nil()) -> |0|() r7: len(cons(X,Z)) -> s(n__len(activate(Z))) r8: fst(X1,X2) -> n__fst(X1,X2) r9: from(X) -> n__from(X) r10: s(X) -> n__s(X) r11: add(X1,X2) -> n__add(X1,X2) r12: len(X) -> n__len(X) r13: activate(n__fst(X1,X2)) -> fst(activate(X1),activate(X2)) r14: activate(n__from(X)) -> from(activate(X)) r15: activate(n__s(X)) -> s(X) r16: activate(n__add(X1,X2)) -> add(activate(X1),activate(X2)) r17: activate(n__len(X)) -> len(activate(X)) r18: activate(X) -> X The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: activate#_A(x1) = ((0,0),(1,0)) x1 + (2,2) n__len_A(x1) = x1 + (1,3) n__fst_A(x1,x2) = ((1,0),(1,1)) x1 + (3,3) n__from_A(x1) = x1 + (3,1) n__add_A(x1,x2) = ((1,0),(0,0)) x1 + ((1,0),(0,0)) x2 + (3,1) precedence: n__fst > activate# > n__len = n__from = n__add partial status: pi(activate#) = [] pi(n__len) = [1] pi(n__fst) = [1] pi(n__from) = [1] pi(n__add) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: activate#_A(x1) = (0,0) n__len_A(x1) = (1,1) n__fst_A(x1,x2) = (1,1) n__from_A(x1) = ((1,0),(0,0)) x1 + (1,1) n__add_A(x1,x2) = (1,1) precedence: n__len = n__from > n__add > activate# = n__fst partial status: pi(activate#) = [] pi(n__len) = [] pi(n__fst) = [] pi(n__from) = [] pi(n__add) = [] The next rules are strictly ordered: p1, p2, p4 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: activate#(n__from(X)) -> activate#(X) p2: activate#(n__add(X1,X2)) -> activate#(X2) and R consists of: r1: fst(|0|(),Z) -> nil() r2: fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z))) r3: from(X) -> cons(X,n__from(n__s(X))) r4: add(|0|(),X) -> X r5: add(s(X),Y) -> s(n__add(activate(X),Y)) r6: len(nil()) -> |0|() r7: len(cons(X,Z)) -> s(n__len(activate(Z))) r8: fst(X1,X2) -> n__fst(X1,X2) r9: from(X) -> n__from(X) r10: s(X) -> n__s(X) r11: add(X1,X2) -> n__add(X1,X2) r12: len(X) -> n__len(X) r13: activate(n__fst(X1,X2)) -> fst(activate(X1),activate(X2)) r14: activate(n__from(X)) -> from(activate(X)) r15: activate(n__s(X)) -> s(X) r16: activate(n__add(X1,X2)) -> add(activate(X1),activate(X2)) r17: activate(n__len(X)) -> len(activate(X)) r18: activate(X) -> 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: activate#(n__from(X)) -> activate#(X) p2: activate#(n__add(X1,X2)) -> activate#(X2) and R consists of: r1: fst(|0|(),Z) -> nil() r2: fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z))) r3: from(X) -> cons(X,n__from(n__s(X))) r4: add(|0|(),X) -> X r5: add(s(X),Y) -> s(n__add(activate(X),Y)) r6: len(nil()) -> |0|() r7: len(cons(X,Z)) -> s(n__len(activate(Z))) r8: fst(X1,X2) -> n__fst(X1,X2) r9: from(X) -> n__from(X) r10: s(X) -> n__s(X) r11: add(X1,X2) -> n__add(X1,X2) r12: len(X) -> n__len(X) r13: activate(n__fst(X1,X2)) -> fst(activate(X1),activate(X2)) r14: activate(n__from(X)) -> from(activate(X)) r15: activate(n__s(X)) -> s(X) r16: activate(n__add(X1,X2)) -> add(activate(X1),activate(X2)) r17: activate(n__len(X)) -> len(activate(X)) r18: activate(X) -> X The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: activate#_A(x1) = x1 n__from_A(x1) = x1 + (1,1) n__add_A(x1,x2) = x1 + ((1,0),(0,0)) x2 + (1,1) precedence: n__from > activate# = n__add partial status: pi(activate#) = [] pi(n__from) = [1] pi(n__add) = [1] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: activate#_A(x1) = (0,0) n__from_A(x1) = (1,1) n__add_A(x1,x2) = x1 + (1,1) precedence: n__add > activate# = n__from partial status: pi(activate#) = [] pi(n__from) = [] pi(n__add) = [1] The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.