YES We show the termination of the relative TRS R/S: R: top(ok(new(x))) -> top(check(x)) top(ok(old(x))) -> top(check(x)) S: bot() -> new(bot()) check(new(x)) -> new(check(x)) check(old(x)) -> old(check(x)) check(old(x)) -> ok(old(x)) new(ok(x)) -> ok(new(x)) old(ok(x)) -> ok(old(x)) -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: top#(ok(new(x))) -> top#(check(x)) p2: top#(ok(old(x))) -> top#(check(x)) and R consists of: r1: top(ok(new(x))) -> top(check(x)) r2: top(ok(old(x))) -> top(check(x)) r3: bot() -> new(bot()) r4: check(new(x)) -> new(check(x)) r5: check(old(x)) -> old(check(x)) r6: check(old(x)) -> ok(old(x)) r7: new(ok(x)) -> ok(new(x)) r8: old(ok(x)) -> ok(old(x)) The estimated dependency graph contains the following SCCs: {p1, p2} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: top#(ok(new(x))) -> top#(check(x)) p2: top#(ok(old(x))) -> top#(check(x)) and R consists of: r1: top(ok(new(x))) -> top(check(x)) r2: top(ok(old(x))) -> top(check(x)) r3: bot() -> new(bot()) r4: check(new(x)) -> new(check(x)) r5: check(old(x)) -> old(check(x)) r6: check(old(x)) -> ok(old(x)) r7: new(ok(x)) -> ok(new(x)) r8: old(ok(x)) -> ok(old(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8 Take the reduction pair: lexicographic combination of reduction pairs: 1. lexicographic path order with precedence: precedence: bot > new > old > top > ok > check > top# argument filter: pi(top#) = [1] pi(ok) = 1 pi(new) = 1 pi(check) = 1 pi(old) = 1 pi(top) = 1 pi(bot) = [] 2. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: top#_A(x1) = ((0,0,0,0),(0,0,0,0),(1,0,0,0),(0,1,0,0)) x1 ok_A(x1) = x1 + (1,1,0,1) new_A(x1) = ((1,0,0,0),(0,1,0,0),(0,0,0,0),(0,1,0,0)) x1 + (0,0,1,1) check_A(x1) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,1,1,0)) x1 + (1,1,1,2) old_A(x1) = x1 + (1,1,0,3) top_A(x1) = x1 bot_A() = (0,0,2,2) The next rules are strictly ordered: p2 We remove them from the problem. -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: top#(ok(new(x))) -> top#(check(x)) and R consists of: r1: top(ok(new(x))) -> top(check(x)) r2: top(ok(old(x))) -> top(check(x)) r3: bot() -> new(bot()) r4: check(new(x)) -> new(check(x)) r5: check(old(x)) -> old(check(x)) r6: check(old(x)) -> ok(old(x)) r7: new(ok(x)) -> ok(new(x)) r8: old(ok(x)) -> ok(old(x)) The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: top#(ok(new(x))) -> top#(check(x)) and R consists of: r1: top(ok(new(x))) -> top(check(x)) r2: top(ok(old(x))) -> top(check(x)) r3: bot() -> new(bot()) r4: check(new(x)) -> new(check(x)) r5: check(old(x)) -> old(check(x)) r6: check(old(x)) -> ok(old(x)) r7: new(ok(x)) -> ok(new(x)) r8: old(ok(x)) -> ok(old(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8 Take the reduction pair: lexicographic combination of reduction pairs: 1. lexicographic path order with precedence: precedence: old > bot > check > top > ok > top# > new argument filter: pi(top#) = 1 pi(ok) = 1 pi(new) = 1 pi(check) = 1 pi(top) = [] pi(old) = [1] pi(bot) = [] 2. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: top#_A(x1) = ((1,0,0,0),(0,1,0,0),(0,1,1,0),(0,0,0,1)) x1 ok_A(x1) = x1 + (0,5,1,3) new_A(x1) = ((1,0,0,0),(1,1,0,0),(0,0,0,0),(0,0,0,0)) x1 + (0,0,3,4) check_A(x1) = ((1,0,0,0),(1,1,0,0),(1,0,0,0),(0,0,1,0)) x1 + (0,1,4,2) top_A(x1) = (0,0,0,0) old_A(x1) = ((1,0,0,0),(0,1,0,0),(0,1,1,0),(0,0,0,0)) x1 + (5,1,0,1) bot_A() = (0,1,4,5) The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.