YES We show the termination of the TRS R: a__2nd(cons1(X,cons(Y,Z))) -> mark(Y) a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1))) a__from(X) -> cons(mark(X),from(s(X))) mark(|2nd|(X)) -> a__2nd(mark(X)) mark(from(X)) -> a__from(mark(X)) mark(cons(X1,X2)) -> cons(mark(X1),X2) mark(s(X)) -> s(mark(X)) mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2)) a__2nd(X) -> |2nd|(X) a__from(X) -> from(X) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: a__2nd#(cons1(X,cons(Y,Z))) -> mark#(Y) p2: a__2nd#(cons(X,X1)) -> a__2nd#(cons1(mark(X),mark(X1))) p3: a__2nd#(cons(X,X1)) -> mark#(X) p4: a__2nd#(cons(X,X1)) -> mark#(X1) p5: a__from#(X) -> mark#(X) p6: mark#(|2nd|(X)) -> a__2nd#(mark(X)) p7: mark#(|2nd|(X)) -> mark#(X) p8: mark#(from(X)) -> a__from#(mark(X)) p9: mark#(from(X)) -> mark#(X) p10: mark#(cons(X1,X2)) -> mark#(X1) p11: mark#(s(X)) -> mark#(X) p12: mark#(cons1(X1,X2)) -> mark#(X1) p13: mark#(cons1(X1,X2)) -> mark#(X2) and R consists of: r1: a__2nd(cons1(X,cons(Y,Z))) -> mark(Y) r2: a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1))) r3: a__from(X) -> cons(mark(X),from(s(X))) r4: mark(|2nd|(X)) -> a__2nd(mark(X)) r5: mark(from(X)) -> a__from(mark(X)) r6: mark(cons(X1,X2)) -> cons(mark(X1),X2) r7: mark(s(X)) -> s(mark(X)) r8: mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2)) r9: a__2nd(X) -> |2nd|(X) r10: a__from(X) -> from(X) The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: a__2nd#(cons1(X,cons(Y,Z))) -> mark#(Y) p2: mark#(cons1(X1,X2)) -> mark#(X2) p3: mark#(cons1(X1,X2)) -> mark#(X1) p4: mark#(s(X)) -> mark#(X) p5: mark#(cons(X1,X2)) -> mark#(X1) p6: mark#(from(X)) -> mark#(X) p7: mark#(from(X)) -> a__from#(mark(X)) p8: a__from#(X) -> mark#(X) p9: mark#(|2nd|(X)) -> mark#(X) p10: mark#(|2nd|(X)) -> a__2nd#(mark(X)) p11: a__2nd#(cons(X,X1)) -> mark#(X1) p12: a__2nd#(cons(X,X1)) -> mark#(X) p13: a__2nd#(cons(X,X1)) -> a__2nd#(cons1(mark(X),mark(X1))) and R consists of: r1: a__2nd(cons1(X,cons(Y,Z))) -> mark(Y) r2: a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1))) r3: a__from(X) -> cons(mark(X),from(s(X))) r4: mark(|2nd|(X)) -> a__2nd(mark(X)) r5: mark(from(X)) -> a__from(mark(X)) r6: mark(cons(X1,X2)) -> cons(mark(X1),X2) r7: mark(s(X)) -> s(mark(X)) r8: mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2)) r9: a__2nd(X) -> |2nd|(X) r10: a__from(X) -> from(X) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10 Take the reduction pair: lexicographic combination of reduction pairs: 1. max/plus interpretations on natural numbers: a__2nd#_A(x1) = x1 + 2 cons1_A(x1,x2) = max{3, x1, x2} cons_A(x1,x2) = max{4, x1 + 2, x2} mark#_A(x1) = max{1, x1 - 3} s_A(x1) = x1 from_A(x1) = x1 + 5 a__from#_A(x1) = x1 + 1 mark_A(x1) = x1 |2nd|_A(x1) = x1 + 6 a__2nd_A(x1) = x1 + 6 a__from_A(x1) = x1 + 5 2. max/plus interpretations on natural numbers: a__2nd#_A(x1) = max{3, x1 + 2} cons1_A(x1,x2) = 0 cons_A(x1,x2) = 3 mark#_A(x1) = 1 s_A(x1) = x1 from_A(x1) = x1 a__from#_A(x1) = x1 + 1 mark_A(x1) = 5 |2nd|_A(x1) = max{1, x1 - 1} a__2nd_A(x1) = max{1, x1 - 1} a__from_A(x1) = max{4, x1} The next rules are strictly ordered: p1, p6, p7, p9, p10, p11, p12, p13 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: mark#(cons1(X1,X2)) -> mark#(X2) p2: mark#(cons1(X1,X2)) -> mark#(X1) p3: mark#(s(X)) -> mark#(X) p4: mark#(cons(X1,X2)) -> mark#(X1) p5: a__from#(X) -> mark#(X) and R consists of: r1: a__2nd(cons1(X,cons(Y,Z))) -> mark(Y) r2: a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1))) r3: a__from(X) -> cons(mark(X),from(s(X))) r4: mark(|2nd|(X)) -> a__2nd(mark(X)) r5: mark(from(X)) -> a__from(mark(X)) r6: mark(cons(X1,X2)) -> cons(mark(X1),X2) r7: mark(s(X)) -> s(mark(X)) r8: mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2)) r9: a__2nd(X) -> |2nd|(X) r10: a__from(X) -> from(X) The estimated dependency graph contains the following SCCs: {p1, p2, p3, p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: mark#(cons1(X1,X2)) -> mark#(X2) p2: mark#(cons(X1,X2)) -> mark#(X1) p3: mark#(s(X)) -> mark#(X) p4: mark#(cons1(X1,X2)) -> mark#(X1) and R consists of: r1: a__2nd(cons1(X,cons(Y,Z))) -> mark(Y) r2: a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1))) r3: a__from(X) -> cons(mark(X),from(s(X))) r4: mark(|2nd|(X)) -> a__2nd(mark(X)) r5: mark(from(X)) -> a__from(mark(X)) r6: mark(cons(X1,X2)) -> cons(mark(X1),X2) r7: mark(s(X)) -> s(mark(X)) r8: mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2)) r9: a__2nd(X) -> |2nd|(X) r10: a__from(X) -> from(X) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. max/plus interpretations on natural numbers: mark#_A(x1) = max{0, x1 - 1} cons1_A(x1,x2) = max{x1 + 2, x2 + 2} cons_A(x1,x2) = max{x1, x2 + 1} s_A(x1) = x1 + 2 2. max/plus interpretations on natural numbers: mark#_A(x1) = 0 cons1_A(x1,x2) = 0 cons_A(x1,x2) = 0 s_A(x1) = x1 + 1 The next rules are strictly ordered: p1, p3, p4 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: mark#(cons(X1,X2)) -> mark#(X1) and R consists of: r1: a__2nd(cons1(X,cons(Y,Z))) -> mark(Y) r2: a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1))) r3: a__from(X) -> cons(mark(X),from(s(X))) r4: mark(|2nd|(X)) -> a__2nd(mark(X)) r5: mark(from(X)) -> a__from(mark(X)) r6: mark(cons(X1,X2)) -> cons(mark(X1),X2) r7: mark(s(X)) -> s(mark(X)) r8: mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2)) r9: a__2nd(X) -> |2nd|(X) r10: a__from(X) -> from(X) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: mark#(cons(X1,X2)) -> mark#(X1) and R consists of: r1: a__2nd(cons1(X,cons(Y,Z))) -> mark(Y) r2: a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1))) r3: a__from(X) -> cons(mark(X),from(s(X))) r4: mark(|2nd|(X)) -> a__2nd(mark(X)) r5: mark(from(X)) -> a__from(mark(X)) r6: mark(cons(X1,X2)) -> cons(mark(X1),X2) r7: mark(s(X)) -> s(mark(X)) r8: mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2)) r9: a__2nd(X) -> |2nd|(X) r10: a__from(X) -> from(X) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. max/plus interpretations on natural numbers: mark#_A(x1) = max{1, x1} cons_A(x1,x2) = max{x1 + 2, x2 + 1} 2. max/plus interpretations on natural numbers: mark#_A(x1) = 0 cons_A(x1,x2) = 0 The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.