YES We show the termination of the relative TRS R/S: R: minus(x,o()) -> x minus(s(x),s(y)) -> minus(x,y) div(|0|(),s(y)) -> |0|() div(s(x),s(y)) -> s(div(minus(x,y),s(y))) divL(x,nil()) -> x divL(x,cons(y,xs)) -> divL(div(x,y),xs) S: cons(x,cons(y,xs)) -> cons(y,cons(x,xs)) -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: minus#(s(x),s(y)) -> minus#(x,y) p2: div#(s(x),s(y)) -> div#(minus(x,y),s(y)) p3: div#(s(x),s(y)) -> minus#(x,y) p4: divL#(x,cons(y,xs)) -> divL#(div(x,y),xs) p5: divL#(x,cons(y,xs)) -> div#(x,y) and R consists of: r1: minus(x,o()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: div(|0|(),s(y)) -> |0|() r4: div(s(x),s(y)) -> s(div(minus(x,y),s(y))) r5: divL(x,nil()) -> x r6: divL(x,cons(y,xs)) -> divL(div(x,y),xs) r7: cons(x,cons(y,xs)) -> cons(y,cons(x,xs)) The estimated dependency graph contains the following SCCs: {p4} {p2} {p1} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: divL#(x,cons(y,xs)) -> divL#(div(x,y),xs) and R consists of: r1: minus(x,o()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: div(|0|(),s(y)) -> |0|() r4: div(s(x),s(y)) -> s(div(minus(x,y),s(y))) r5: divL(x,nil()) -> x r6: divL(x,cons(y,xs)) -> divL(div(x,y),xs) r7: cons(x,cons(y,xs)) -> cons(y,cons(x,xs)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7 Take the reduction pair: lexicographic combination of reduction pairs: 1. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: divL#_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(1,0,0,0),(0,1,1,0)) x1 + ((1,0,0,0),(1,1,0,0),(0,0,1,0),(0,1,1,1)) x2 cons_A(x1,x2) = ((1,0,0,0),(1,1,0,0),(1,1,1,0),(0,1,1,1)) x1 + x2 + (9,1,1,1) div_A(x1,x2) = ((1,0,0,0),(1,1,0,0),(1,1,1,0),(1,0,1,1)) x1 + ((0,0,0,0),(1,0,0,0),(1,1,0,0),(1,1,1,0)) x2 + (8,11,2,1) minus_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,1,1,0),(1,0,0,0)) x1 + (0,1,1,1) o_A() = (1,1,1,1) s_A(x1) = ((1,0,0,0),(0,1,0,0),(1,0,1,0),(1,0,0,0)) x1 + (2,1,1,1) |0|_A() = (1,1,1,1) divL_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(1,1,1,1)) x1 + ((1,0,0,0),(0,0,0,0),(0,1,0,0),(1,1,1,0)) x2 + (0,1,0,0) nil_A() = (1,1,1,1) 2. lexicographic path order with precedence: precedence: nil > cons > divL > div > minus > o > |0| > s > divL# argument filter: pi(divL#) = 2 pi(cons) = [] pi(div) = 1 pi(minus) = [] pi(o) = [] pi(s) = [] pi(|0|) = [] pi(divL) = [1] pi(nil) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: div#(s(x),s(y)) -> div#(minus(x,y),s(y)) and R consists of: r1: minus(x,o()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: div(|0|(),s(y)) -> |0|() r4: div(s(x),s(y)) -> s(div(minus(x,y),s(y))) r5: divL(x,nil()) -> x r6: divL(x,cons(y,xs)) -> divL(div(x,y),xs) r7: cons(x,cons(y,xs)) -> cons(y,cons(x,xs)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7 Take the reduction pair: lexicographic combination of reduction pairs: 1. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: div#_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,1,1,0),(0,1,1,0)) x1 + ((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,1,1,1)) x2 s_A(x1) = x1 + (0,1,1,1) minus_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,1,1,0),(0,0,1,1)) x1 + (0,0,3,1) o_A() = (1,1,1,0) div_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(1,0,0,0)) x1 + ((0,0,0,0),(0,0,0,0),(1,0,0,0),(1,1,0,0)) x2 + (1,1,1,6) |0|_A() = (1,1,1,9) divL_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,1,1,1)) x1 + ((1,0,0,0),(0,1,0,0),(0,0,1,0),(1,1,1,1)) x2 nil_A() = (1,1,1,1) cons_A(x1,x2) = ((1,0,0,0),(1,1,0,0),(1,1,1,0),(1,1,1,1)) x1 + x2 + (2,2,2,1) 2. lexicographic path order with precedence: precedence: cons > divL > div > minus > div# > o > nil > |0| > s argument filter: pi(div#) = 2 pi(s) = [] pi(minus) = [] pi(o) = [] pi(div) = [] pi(|0|) = [] pi(divL) = 1 pi(nil) = [] pi(cons) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: minus#(s(x),s(y)) -> minus#(x,y) and R consists of: r1: minus(x,o()) -> x r2: minus(s(x),s(y)) -> minus(x,y) r3: div(|0|(),s(y)) -> |0|() r4: div(s(x),s(y)) -> s(div(minus(x,y),s(y))) r5: divL(x,nil()) -> x r6: divL(x,cons(y,xs)) -> divL(div(x,y),xs) r7: cons(x,cons(y,xs)) -> cons(y,cons(x,xs)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7 Take the reduction pair: lexicographic combination of reduction pairs: 1. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: minus#_A(x1,x2) = ((0,0,0,0),(0,0,0,0),(0,0,0,0),(1,0,0,0)) x2 s_A(x1) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(1,0,1,0)) x1 + (1,1,2,1) minus_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(1,1,1,1)) x1 + ((0,0,0,0),(0,0,0,0),(1,0,0,0),(0,0,0,0)) x2 + (0,0,0,1) o_A() = (1,1,0,1) div_A(x1,x2) = ((1,0,0,0),(1,1,0,0),(0,1,0,0),(0,0,1,0)) x1 + ((1,0,0,0),(0,1,0,0),(0,1,1,0),(0,0,0,0)) x2 + (3,4,1,1) |0|_A() = (1,1,6,8) divL_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,0,0,0),(1,1,1,0)) x1 + ((1,0,0,0),(1,1,0,0),(1,1,1,0),(1,1,1,1)) x2 nil_A() = (1,1,1,1) cons_A(x1,x2) = ((1,0,0,0),(1,1,0,0),(1,1,1,0),(0,0,1,1)) x1 + x2 + (4,1,1,1) 2. lexicographic path order with precedence: precedence: o > |0| > minus > nil > divL > cons > div > s > minus# argument filter: pi(minus#) = [] pi(s) = [] pi(minus) = [1] pi(o) = [] pi(div) = [] pi(|0|) = [] pi(divL) = [] pi(nil) = [] pi(cons) = [2] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.