/export/starexec/sandbox2/solver/bin/starexec_run_complexity /export/starexec/sandbox2/benchmark/theBenchmark.xml /export/starexec/sandbox2/output/output_files -------------------------------------------------------------------------------- WORST_CASE(Omega(n^1), O(n^2)) proof of /export/starexec/sandbox2/benchmark/theBenchmark.xml # AProVE Commit ID: 48fb2092695e11cc9f56e44b17a92a5f88ffb256 marcel 20180622 unpublished dirty The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(n^1, n^2). (0) CpxTRS (1) CpxTrsToCdtProof [UPPER BOUND(ID), 0 ms] (2) CdtProblem (3) CdtLeafRemovalProof [BOTH BOUNDS(ID, ID), 0 ms] (4) CdtProblem (5) CdtRuleRemovalProof [UPPER BOUND(ADD(n^1)), 119 ms] (6) CdtProblem (7) CdtKnowledgeProof [BOTH BOUNDS(ID, ID), 0 ms] (8) CdtProblem (9) CdtRuleRemovalProof [UPPER BOUND(ADD(n^2)), 118 ms] (10) CdtProblem (11) CdtKnowledgeProof [FINISHED, 0 ms] (12) BOUNDS(1, 1) (13) RelTrsToDecreasingLoopProblemProof [LOWER BOUND(ID), 0 ms] (14) TRS for Loop Detection (15) DecreasingLoopProof [LOWER BOUND(ID), 0 ms] (16) BEST (17) proven lower bound (18) LowerBoundPropagationProof [FINISHED, 0 ms] (19) BOUNDS(n^1, INF) (20) TRS for Loop Detection ---------------------------------------- (0) Obligation: The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(n^1, n^2). The TRS R consists of the following rules: append(@l1, @l2) -> append#1(@l1, @l2) append#1(::(@x, @xs), @l2) -> ::(@x, append(@xs, @l2)) append#1(nil, @l2) -> @l2 subtrees(@t) -> subtrees#1(@t) subtrees#1(leaf) -> nil subtrees#1(node(@x, @t1, @t2)) -> subtrees#2(subtrees(@t1), @t1, @t2, @x) subtrees#2(@l1, @t1, @t2, @x) -> subtrees#3(subtrees(@t2), @l1, @t1, @t2, @x) subtrees#3(@l2, @l1, @t1, @t2, @x) -> ::(node(@x, @t1, @t2), append(@l1, @l2)) S is empty. Rewrite Strategy: INNERMOST ---------------------------------------- (1) CpxTrsToCdtProof (UPPER BOUND(ID)) Converted Cpx (relative) TRS to CDT ---------------------------------------- (2) Obligation: Complexity Dependency Tuples Problem Rules: append(z0, z1) -> append#1(z0, z1) append#1(::(z0, z1), z2) -> ::(z0, append(z1, z2)) append#1(nil, z0) -> z0 subtrees(z0) -> subtrees#1(z0) subtrees#1(leaf) -> nil subtrees#1(node(z0, z1, z2)) -> subtrees#2(subtrees(z1), z1, z2, z0) subtrees#2(z0, z1, z2, z3) -> subtrees#3(subtrees(z2), z0, z1, z2, z3) subtrees#3(z0, z1, z2, z3, z4) -> ::(node(z4, z2, z3), append(z1, z0)) Tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) APPEND#1(nil, z0) -> c2 SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(leaf) -> c4 SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) S tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) APPEND#1(nil, z0) -> c2 SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(leaf) -> c4 SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) K tuples:none Defined Rule Symbols: append_2, append#1_2, subtrees_1, subtrees#1_1, subtrees#2_4, subtrees#3_5 Defined Pair Symbols: APPEND_2, APPEND#1_2, SUBTREES_1, SUBTREES#1_1, SUBTREES#2_4, SUBTREES#3_5 Compound Symbols: c_1, c1_1, c2, c3_1, c4, c5_2, c6_2, c7_1 ---------------------------------------- (3) CdtLeafRemovalProof (BOTH BOUNDS(ID, ID)) Removed 2 trailing nodes: APPEND#1(nil, z0) -> c2 SUBTREES#1(leaf) -> c4 ---------------------------------------- (4) Obligation: Complexity Dependency Tuples Problem Rules: append(z0, z1) -> append#1(z0, z1) append#1(::(z0, z1), z2) -> ::(z0, append(z1, z2)) append#1(nil, z0) -> z0 subtrees(z0) -> subtrees#1(z0) subtrees#1(leaf) -> nil subtrees#1(node(z0, z1, z2)) -> subtrees#2(subtrees(z1), z1, z2, z0) subtrees#2(z0, z1, z2, z3) -> subtrees#3(subtrees(z2), z0, z1, z2, z3) subtrees#3(z0, z1, z2, z3, z4) -> ::(node(z4, z2, z3), append(z1, z0)) Tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) S tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) K tuples:none Defined Rule Symbols: append_2, append#1_2, subtrees_1, subtrees#1_1, subtrees#2_4, subtrees#3_5 Defined Pair Symbols: APPEND_2, APPEND#1_2, SUBTREES_1, SUBTREES#1_1, SUBTREES#2_4, SUBTREES#3_5 Compound Symbols: c_1, c1_1, c3_1, c5_2, c6_2, c7_1 ---------------------------------------- (5) CdtRuleRemovalProof (UPPER BOUND(ADD(n^1))) Found a reduction pair which oriented the following tuples strictly. Hence they can be removed from S. SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) We considered the (Usable) Rules: subtrees#3(z0, z1, z2, z3, z4) -> ::(node(z4, z2, z3), append(z1, z0)) subtrees#2(z0, z1, z2, z3) -> subtrees#3(subtrees(z2), z0, z1, z2, z3) append(z0, z1) -> append#1(z0, z1) append#1(nil, z0) -> z0 subtrees(z0) -> subtrees#1(z0) subtrees#1(node(z0, z1, z2)) -> subtrees#2(subtrees(z1), z1, z2, z0) subtrees#1(leaf) -> nil append#1(::(z0, z1), z2) -> ::(z0, append(z1, z2)) And the Tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) The order we found is given by the following interpretation: Polynomial interpretation : POL(::(x_1, x_2)) = x_2 POL(APPEND(x_1, x_2)) = x_1 + x_2 POL(APPEND#1(x_1, x_2)) = x_1 + x_2 POL(SUBTREES(x_1)) = x_1 POL(SUBTREES#1(x_1)) = x_1 POL(SUBTREES#2(x_1, x_2, x_3, x_4)) = x_1 + x_3 + x_4 POL(SUBTREES#3(x_1, x_2, x_3, x_4, x_5)) = x_1 + x_2 + x_5 POL(append(x_1, x_2)) = x_1 + x_2 POL(append#1(x_1, x_2)) = x_1 + x_2 POL(c(x_1)) = x_1 POL(c1(x_1)) = x_1 POL(c3(x_1)) = x_1 POL(c5(x_1, x_2)) = x_1 + x_2 POL(c6(x_1, x_2)) = x_1 + x_2 POL(c7(x_1)) = x_1 POL(leaf) = [1] POL(nil) = 0 POL(node(x_1, x_2, x_3)) = [1] + x_1 + x_2 + x_3 POL(subtrees(x_1)) = 0 POL(subtrees#1(x_1)) = 0 POL(subtrees#2(x_1, x_2, x_3, x_4)) = x_1 POL(subtrees#3(x_1, x_2, x_3, x_4, x_5)) = x_1 + x_2 ---------------------------------------- (6) Obligation: Complexity Dependency Tuples Problem Rules: append(z0, z1) -> append#1(z0, z1) append#1(::(z0, z1), z2) -> ::(z0, append(z1, z2)) append#1(nil, z0) -> z0 subtrees(z0) -> subtrees#1(z0) subtrees#1(leaf) -> nil subtrees#1(node(z0, z1, z2)) -> subtrees#2(subtrees(z1), z1, z2, z0) subtrees#2(z0, z1, z2, z3) -> subtrees#3(subtrees(z2), z0, z1, z2, z3) subtrees#3(z0, z1, z2, z3, z4) -> ::(node(z4, z2, z3), append(z1, z0)) Tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) S tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) K tuples: SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) Defined Rule Symbols: append_2, append#1_2, subtrees_1, subtrees#1_1, subtrees#2_4, subtrees#3_5 Defined Pair Symbols: APPEND_2, APPEND#1_2, SUBTREES_1, SUBTREES#1_1, SUBTREES#2_4, SUBTREES#3_5 Compound Symbols: c_1, c1_1, c3_1, c5_2, c6_2, c7_1 ---------------------------------------- (7) CdtKnowledgeProof (BOTH BOUNDS(ID, ID)) The following tuples could be moved from S to K by knowledge propagation: SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) ---------------------------------------- (8) Obligation: Complexity Dependency Tuples Problem Rules: append(z0, z1) -> append#1(z0, z1) append#1(::(z0, z1), z2) -> ::(z0, append(z1, z2)) append#1(nil, z0) -> z0 subtrees(z0) -> subtrees#1(z0) subtrees#1(leaf) -> nil subtrees#1(node(z0, z1, z2)) -> subtrees#2(subtrees(z1), z1, z2, z0) subtrees#2(z0, z1, z2, z3) -> subtrees#3(subtrees(z2), z0, z1, z2, z3) subtrees#3(z0, z1, z2, z3, z4) -> ::(node(z4, z2, z3), append(z1, z0)) Tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) S tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) K tuples: SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) Defined Rule Symbols: append_2, append#1_2, subtrees_1, subtrees#1_1, subtrees#2_4, subtrees#3_5 Defined Pair Symbols: APPEND_2, APPEND#1_2, SUBTREES_1, SUBTREES#1_1, SUBTREES#2_4, SUBTREES#3_5 Compound Symbols: c_1, c1_1, c3_1, c5_2, c6_2, c7_1 ---------------------------------------- (9) CdtRuleRemovalProof (UPPER BOUND(ADD(n^2))) Found a reduction pair which oriented the following tuples strictly. Hence they can be removed from S. APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) We considered the (Usable) Rules: subtrees#3(z0, z1, z2, z3, z4) -> ::(node(z4, z2, z3), append(z1, z0)) subtrees#2(z0, z1, z2, z3) -> subtrees#3(subtrees(z2), z0, z1, z2, z3) append(z0, z1) -> append#1(z0, z1) append#1(nil, z0) -> z0 subtrees(z0) -> subtrees#1(z0) subtrees#1(node(z0, z1, z2)) -> subtrees#2(subtrees(z1), z1, z2, z0) subtrees#1(leaf) -> nil append#1(::(z0, z1), z2) -> ::(z0, append(z1, z2)) And the Tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) The order we found is given by the following interpretation: Polynomial interpretation : POL(::(x_1, x_2)) = [2] + x_2 POL(APPEND(x_1, x_2)) = [2]x_1 POL(APPEND#1(x_1, x_2)) = [2]x_1 POL(SUBTREES(x_1)) = x_1^2 POL(SUBTREES#1(x_1)) = x_1^2 POL(SUBTREES#2(x_1, x_2, x_3, x_4)) = [2]x_1 + x_3^2 + [2]x_2*x_3 POL(SUBTREES#3(x_1, x_2, x_3, x_4, x_5)) = [2]x_2 + x_3*x_4 POL(append(x_1, x_2)) = x_1 + x_2 POL(append#1(x_1, x_2)) = x_1 + x_2 POL(c(x_1)) = x_1 POL(c1(x_1)) = x_1 POL(c3(x_1)) = x_1 POL(c5(x_1, x_2)) = x_1 + x_2 POL(c6(x_1, x_2)) = x_1 + x_2 POL(c7(x_1)) = x_1 POL(leaf) = 0 POL(nil) = 0 POL(node(x_1, x_2, x_3)) = [2] + x_2 + x_3 POL(subtrees(x_1)) = [2]x_1 POL(subtrees#1(x_1)) = [2]x_1 POL(subtrees#2(x_1, x_2, x_3, x_4)) = [2] + x_1 + [2]x_3 POL(subtrees#3(x_1, x_2, x_3, x_4, x_5)) = [2] + x_1 + x_2 ---------------------------------------- (10) Obligation: Complexity Dependency Tuples Problem Rules: append(z0, z1) -> append#1(z0, z1) append#1(::(z0, z1), z2) -> ::(z0, append(z1, z2)) append#1(nil, z0) -> z0 subtrees(z0) -> subtrees#1(z0) subtrees#1(leaf) -> nil subtrees#1(node(z0, z1, z2)) -> subtrees#2(subtrees(z1), z1, z2, z0) subtrees#2(z0, z1, z2, z3) -> subtrees#3(subtrees(z2), z0, z1, z2, z3) subtrees#3(z0, z1, z2, z3, z4) -> ::(node(z4, z2, z3), append(z1, z0)) Tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) S tuples: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) K tuples: SUBTREES#1(node(z0, z1, z2)) -> c5(SUBTREES#2(subtrees(z1), z1, z2, z0), SUBTREES(z1)) SUBTREES#2(z0, z1, z2, z3) -> c6(SUBTREES#3(subtrees(z2), z0, z1, z2, z3), SUBTREES(z2)) SUBTREES#3(z0, z1, z2, z3, z4) -> c7(APPEND(z1, z0)) SUBTREES(z0) -> c3(SUBTREES#1(z0)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) Defined Rule Symbols: append_2, append#1_2, subtrees_1, subtrees#1_1, subtrees#2_4, subtrees#3_5 Defined Pair Symbols: APPEND_2, APPEND#1_2, SUBTREES_1, SUBTREES#1_1, SUBTREES#2_4, SUBTREES#3_5 Compound Symbols: c_1, c1_1, c3_1, c5_2, c6_2, c7_1 ---------------------------------------- (11) CdtKnowledgeProof (FINISHED) The following tuples could be moved from S to K by knowledge propagation: APPEND(z0, z1) -> c(APPEND#1(z0, z1)) APPEND#1(::(z0, z1), z2) -> c1(APPEND(z1, z2)) Now S is empty ---------------------------------------- (12) BOUNDS(1, 1) ---------------------------------------- (13) RelTrsToDecreasingLoopProblemProof (LOWER BOUND(ID)) Transformed a relative TRS into a decreasing-loop problem. ---------------------------------------- (14) Obligation: Analyzing the following TRS for decreasing loops: The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(n^1, n^2). The TRS R consists of the following rules: append(@l1, @l2) -> append#1(@l1, @l2) append#1(::(@x, @xs), @l2) -> ::(@x, append(@xs, @l2)) append#1(nil, @l2) -> @l2 subtrees(@t) -> subtrees#1(@t) subtrees#1(leaf) -> nil subtrees#1(node(@x, @t1, @t2)) -> subtrees#2(subtrees(@t1), @t1, @t2, @x) subtrees#2(@l1, @t1, @t2, @x) -> subtrees#3(subtrees(@t2), @l1, @t1, @t2, @x) subtrees#3(@l2, @l1, @t1, @t2, @x) -> ::(node(@x, @t1, @t2), append(@l1, @l2)) S is empty. Rewrite Strategy: INNERMOST ---------------------------------------- (15) DecreasingLoopProof (LOWER BOUND(ID)) The following loop(s) give(s) rise to the lower bound Omega(n^1): The rewrite sequence subtrees(node(@x1_0, @t12_0, @t23_0)) ->^+ subtrees#2(subtrees(@t12_0), @t12_0, @t23_0, @x1_0) gives rise to a decreasing loop by considering the right hand sides subterm at position [0]. The pumping substitution is [@t12_0 / node(@x1_0, @t12_0, @t23_0)]. The result substitution is [ ]. ---------------------------------------- (16) Complex Obligation (BEST) ---------------------------------------- (17) Obligation: Proved the lower bound n^1 for the following obligation: The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(n^1, n^2). The TRS R consists of the following rules: append(@l1, @l2) -> append#1(@l1, @l2) append#1(::(@x, @xs), @l2) -> ::(@x, append(@xs, @l2)) append#1(nil, @l2) -> @l2 subtrees(@t) -> subtrees#1(@t) subtrees#1(leaf) -> nil subtrees#1(node(@x, @t1, @t2)) -> subtrees#2(subtrees(@t1), @t1, @t2, @x) subtrees#2(@l1, @t1, @t2, @x) -> subtrees#3(subtrees(@t2), @l1, @t1, @t2, @x) subtrees#3(@l2, @l1, @t1, @t2, @x) -> ::(node(@x, @t1, @t2), append(@l1, @l2)) S is empty. Rewrite Strategy: INNERMOST ---------------------------------------- (18) LowerBoundPropagationProof (FINISHED) Propagated lower bound. ---------------------------------------- (19) BOUNDS(n^1, INF) ---------------------------------------- (20) Obligation: Analyzing the following TRS for decreasing loops: The Runtime Complexity (innermost) of the given CpxTRS could be proven to be BOUNDS(n^1, n^2). The TRS R consists of the following rules: append(@l1, @l2) -> append#1(@l1, @l2) append#1(::(@x, @xs), @l2) -> ::(@x, append(@xs, @l2)) append#1(nil, @l2) -> @l2 subtrees(@t) -> subtrees#1(@t) subtrees#1(leaf) -> nil subtrees#1(node(@x, @t1, @t2)) -> subtrees#2(subtrees(@t1), @t1, @t2, @x) subtrees#2(@l1, @t1, @t2, @x) -> subtrees#3(subtrees(@t2), @l1, @t1, @t2, @x) subtrees#3(@l2, @l1, @t1, @t2, @x) -> ::(node(@x, @t1, @t2), append(@l1, @l2)) S is empty. Rewrite Strategy: INNERMOST