YES We show the termination of the relative TRS R/S: R: +(|0|(),y) -> y +(s(x),y) -> s(+(x,y)) sum1(nil()) -> |0|() sum1(cons(x,y)) -> +(x,sum1(y)) sum2(nil(),z) -> z sum2(cons(x,y),z) -> sum2(y,+(x,z)) tests(|0|()) -> true() tests(s(x)) -> and(test(rands(rand(|0|()),nil())),x) test(done(y)) -> eq(f(y),g(y)) eq(x,x) -> true() rands(|0|(),y) -> done(y) rands(s(x),y) -> rands(x,|::|(rand(|0|()),y)) S: rand(x) -> x rand(x) -> rand(s(x)) -- SCC decomposition. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: +#(s(x),y) -> +#(x,y) p2: sum1#(cons(x,y)) -> +#(x,sum1(y)) p3: sum1#(cons(x,y)) -> sum1#(y) p4: sum2#(cons(x,y),z) -> sum2#(y,+(x,z)) p5: sum2#(cons(x,y),z) -> +#(x,z) p6: tests#(s(x)) -> test#(rands(rand(|0|()),nil())) p7: tests#(s(x)) -> rands#(rand(|0|()),nil()) p8: test#(done(y)) -> eq#(f(y),g(y)) p9: rands#(s(x),y) -> rands#(x,|::|(rand(|0|()),y)) and R consists of: r1: +(|0|(),y) -> y r2: +(s(x),y) -> s(+(x,y)) r3: sum1(nil()) -> |0|() r4: sum1(cons(x,y)) -> +(x,sum1(y)) r5: sum2(nil(),z) -> z r6: sum2(cons(x,y),z) -> sum2(y,+(x,z)) r7: tests(|0|()) -> true() r8: tests(s(x)) -> and(test(rands(rand(|0|()),nil())),x) r9: test(done(y)) -> eq(f(y),g(y)) r10: eq(x,x) -> true() r11: rands(|0|(),y) -> done(y) r12: rands(s(x),y) -> rands(x,|::|(rand(|0|()),y)) r13: rand(x) -> x r14: rand(x) -> rand(s(x)) The estimated dependency graph contains the following SCCs: {p4} {p3} {p1} {p9} -- Reduction pair. Consider the non-minimal dependency pair problem (P, R), where P consists of p1: sum2#(cons(x,y),z) -> sum2#(y,+(x,z)) and R consists of: r1: +(|0|(),y) -> y r2: +(s(x),y) -> s(+(x,y)) r3: sum1(nil()) -> |0|() r4: sum1(cons(x,y)) -> +(x,sum1(y)) r5: sum2(nil(),z) -> z r6: sum2(cons(x,y),z) -> sum2(y,+(x,z)) r7: tests(|0|()) -> true() r8: tests(s(x)) -> and(test(rands(rand(|0|()),nil())),x) r9: test(done(y)) -> eq(f(y),g(y)) r10: eq(x,x) -> true() r11: rands(|0|(),y) -> done(y) r12: rands(s(x),y) -> rands(x,|::|(rand(|0|()),y)) r13: rand(x) -> x r14: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: sum2#_A(x1,x2) = x1 + x2 + 4 cons_A(x1,x2) = x1 + x2 + 4 +_A(x1,x2) = x1 + x2 + 1 |0|_A() = 4 s_A(x1) = x1 sum1_A(x1) = x1 + 2 nil_A() = 3 sum2_A(x1,x2) = x1 + x2 + 4 tests_A(x1) = x1 + 6 true_A() = 1 and_A(x1,x2) = 1 test_A(x1) = 3 rands_A(x1,x2) = x1 rand_A(x1) = x1 + 1 done_A(x1) = 3 eq_A(x1,x2) = 2 f_A(x1) = 1 g_A(x1) = 1 |::|_A(x1,x2) = 1 precedence: cons = + = |0| > s = sum1 = nil = sum2 = true = and = test = eq = g > tests = rands = rand = done = f = |::| > sum2# partial status: pi(sum2#) = [] pi(cons) = [2] pi(+) = [1, 2] pi(|0|) = [] pi(s) = [1] pi(sum1) = [1] pi(nil) = [] pi(sum2) = [1, 2] pi(tests) = [1] pi(true) = [] pi(and) = [] pi(test) = [] pi(rands) = [1] pi(rand) = [] pi(done) = [] pi(eq) = [] pi(f) = [] pi(g) = [] pi(|::|) = [] 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: sum1#(cons(x,y)) -> sum1#(y) and R consists of: r1: +(|0|(),y) -> y r2: +(s(x),y) -> s(+(x,y)) r3: sum1(nil()) -> |0|() r4: sum1(cons(x,y)) -> +(x,sum1(y)) r5: sum2(nil(),z) -> z r6: sum2(cons(x,y),z) -> sum2(y,+(x,z)) r7: tests(|0|()) -> true() r8: tests(s(x)) -> and(test(rands(rand(|0|()),nil())),x) r9: test(done(y)) -> eq(f(y),g(y)) r10: eq(x,x) -> true() r11: rands(|0|(),y) -> done(y) r12: rands(s(x),y) -> rands(x,|::|(rand(|0|()),y)) r13: rand(x) -> x r14: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: sum1#_A(x1) = x1 cons_A(x1,x2) = x1 + x2 + 3 +_A(x1,x2) = x2 + 1 |0|_A() = 0 s_A(x1) = x1 sum1_A(x1) = x1 + 1 nil_A() = 1 sum2_A(x1,x2) = x1 + x2 + 1 tests_A(x1) = x1 + 3 true_A() = 0 and_A(x1,x2) = 1 test_A(x1) = 2 rands_A(x1,x2) = x1 + 2 rand_A(x1) = x1 + 4 done_A(x1) = 1 eq_A(x1,x2) = 1 f_A(x1) = 1 g_A(x1) = 1 |::|_A(x1,x2) = 1 precedence: sum1# = cons = + > |0| = sum1 = nil = sum2 = true = and = test = rands = f > tests = rand = done = eq = g = |::| > s partial status: pi(sum1#) = [] pi(cons) = [2] pi(+) = [2] pi(|0|) = [] pi(s) = [] pi(sum1) = [] pi(nil) = [] pi(sum2) = [] pi(tests) = [1] pi(true) = [] pi(and) = [] pi(test) = [] pi(rands) = [] pi(rand) = [1] pi(done) = [] pi(eq) = [] pi(f) = [] pi(g) = [] pi(|::|) = [] 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: +#(s(x),y) -> +#(x,y) and R consists of: r1: +(|0|(),y) -> y r2: +(s(x),y) -> s(+(x,y)) r3: sum1(nil()) -> |0|() r4: sum1(cons(x,y)) -> +(x,sum1(y)) r5: sum2(nil(),z) -> z r6: sum2(cons(x,y),z) -> sum2(y,+(x,z)) r7: tests(|0|()) -> true() r8: tests(s(x)) -> and(test(rands(rand(|0|()),nil())),x) r9: test(done(y)) -> eq(f(y),g(y)) r10: eq(x,x) -> true() r11: rands(|0|(),y) -> done(y) r12: rands(s(x),y) -> rands(x,|::|(rand(|0|()),y)) r13: rand(x) -> x r14: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: +#_A(x1,x2) = x1 s_A(x1) = x1 +_A(x1,x2) = x1 + x2 + 2 |0|_A() = 4 sum1_A(x1) = x1 + 2 nil_A() = 3 cons_A(x1,x2) = x1 + x2 + 3 sum2_A(x1,x2) = x1 + x2 + 2 tests_A(x1) = x1 + 12 true_A() = 1 and_A(x1,x2) = 1 test_A(x1) = 3 rands_A(x1,x2) = x1 + 6 rand_A(x1) = x1 + 1 done_A(x1) = 3 eq_A(x1,x2) = 2 f_A(x1) = 1 g_A(x1) = x1 + 4 |::|_A(x1,x2) = 1 precedence: + = |0| = sum1 > +# = s = nil = cons = sum2 = tests = true = test = rands = f > and = done = g = |::| > rand = eq partial status: pi(+#) = [1] pi(s) = [1] pi(+) = [1] pi(|0|) = [] pi(sum1) = [1] pi(nil) = [] pi(cons) = [2] pi(sum2) = [1, 2] pi(tests) = [1] pi(true) = [] pi(and) = [] pi(test) = [] pi(rands) = [1] pi(rand) = [] pi(done) = [] pi(eq) = [] pi(f) = [] pi(g) = [1] pi(|::|) = [] 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: rands#(s(x),y) -> rands#(x,|::|(rand(|0|()),y)) and R consists of: r1: +(|0|(),y) -> y r2: +(s(x),y) -> s(+(x,y)) r3: sum1(nil()) -> |0|() r4: sum1(cons(x,y)) -> +(x,sum1(y)) r5: sum2(nil(),z) -> z r6: sum2(cons(x,y),z) -> sum2(y,+(x,z)) r7: tests(|0|()) -> true() r8: tests(s(x)) -> and(test(rands(rand(|0|()),nil())),x) r9: test(done(y)) -> eq(f(y),g(y)) r10: eq(x,x) -> true() r11: rands(|0|(),y) -> done(y) r12: rands(s(x),y) -> rands(x,|::|(rand(|0|()),y)) r13: rand(x) -> x r14: rand(x) -> rand(s(x)) The set of usable rules consists of r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14 Take the reduction pair: weighted path order base order: matrix interpretations: carrier: N^1 order: lexicographic order interpretations: rands#_A(x1,x2) = x1 + x2 + 6 s_A(x1) = x1 |::|_A(x1,x2) = x2 rand_A(x1) = x1 + 1 |0|_A() = 4 +_A(x1,x2) = x1 + x2 + 1 sum1_A(x1) = x1 + 3 nil_A() = 3 cons_A(x1,x2) = x1 + x2 + 2 sum2_A(x1,x2) = x1 + x2 + 2 tests_A(x1) = x1 + 2 true_A() = 1 and_A(x1,x2) = 1 test_A(x1) = 3 rands_A(x1,x2) = x1 + x2 + 1 done_A(x1) = 3 eq_A(x1,x2) = 2 f_A(x1) = 1 g_A(x1) = 1 precedence: |::| = rand = |0| = sum1 = nil > + = cons = sum2 = true > tests = test = rands = done = eq = f > g > rands# > s = and partial status: pi(rands#) = [1] pi(s) = [1] pi(|::|) = [] pi(rand) = [] pi(|0|) = [] pi(+) = [1] pi(sum1) = [] pi(nil) = [] pi(cons) = [2] pi(sum2) = [] pi(tests) = [1] pi(true) = [] pi(and) = [] pi(test) = [] pi(rands) = [1] pi(done) = [] pi(eq) = [] pi(f) = [] pi(g) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.