WORST_CASE(Omega(n^1),?) ### Pre-processing the ITS problem ### Initial linear ITS problem Start location: l4 0: l0 -> l1 : x^0'=x^post_1, y^0'=y^post_1, z^0'=z^post_1, [ x^0==x^post_1 && y^0==y^post_1 && z^0==z^post_1 ], cost: 1 4: l1 -> l2 : x^0'=x^post_5, y^0'=y^post_5, z^0'=z^post_5, [ 1+x^0<=y^0 && x^0==x^post_5 && y^0==y^post_5 && z^0==z^post_5 ], cost: 1 1: l2 -> l1 : x^0'=x^post_2, y^0'=y^post_2, z^0'=z^post_2, [ z^0<=y^0 && x^post_2==1+x^0 && y^0==y^post_2 && z^0==z^post_2 ], cost: 1 2: l2 -> l3 : x^0'=x^post_3, y^0'=y^post_3, z^0'=z^post_3, [ 1+y^0<=z^0 && y^post_3==1+y^0 && x^0==x^post_3 && z^0==z^post_3 ], cost: 1 3: l3 -> l2 : x^0'=x^post_4, y^0'=y^post_4, z^0'=z^post_4, [ x^0==x^post_4 && y^0==y^post_4 && z^0==z^post_4 ], cost: 1 5: l4 -> l0 : x^0'=x^post_6, y^0'=y^post_6, z^0'=z^post_6, [ x^0==x^post_6 && y^0==y^post_6 && z^0==z^post_6 ], cost: 1 Checking for constant complexity: The following rule is satisfiable with cost >= 1, yielding constant complexity: 5: l4 -> l0 : x^0'=x^post_6, y^0'=y^post_6, z^0'=z^post_6, [ x^0==x^post_6 && y^0==y^post_6 && z^0==z^post_6 ], cost: 1 Simplified all rules, resulting in: Start location: l4 0: l0 -> l1 : [], cost: 1 4: l1 -> l2 : [ 1+x^0<=y^0 ], cost: 1 1: l2 -> l1 : x^0'=1+x^0, [ z^0<=y^0 ], cost: 1 2: l2 -> l3 : y^0'=1+y^0, [ 1+y^0<=z^0 ], cost: 1 3: l3 -> l2 : [], cost: 1 5: l4 -> l0 : [], cost: 1 ### Simplification by acceleration and chaining ### Eliminated locations (on linear paths): Start location: l4 4: l1 -> l2 : [ 1+x^0<=y^0 ], cost: 1 1: l2 -> l1 : x^0'=1+x^0, [ z^0<=y^0 ], cost: 1 7: l2 -> l2 : y^0'=1+y^0, [ 1+y^0<=z^0 ], cost: 2 6: l4 -> l1 : [], cost: 2 Accelerating simple loops of location 2. Accelerating the following rules: 7: l2 -> l2 : y^0'=1+y^0, [ 1+y^0<=z^0 ], cost: 2 Accelerated rule 7 with metering function z^0-y^0, yielding the new rule 8. Removing the simple loops: 7. Accelerated all simple loops using metering functions (where possible): Start location: l4 4: l1 -> l2 : [ 1+x^0<=y^0 ], cost: 1 1: l2 -> l1 : x^0'=1+x^0, [ z^0<=y^0 ], cost: 1 8: l2 -> l2 : y^0'=z^0, [ 1+y^0<=z^0 ], cost: 2*z^0-2*y^0 6: l4 -> l1 : [], cost: 2 Chained accelerated rules (with incoming rules): Start location: l4 4: l1 -> l2 : [ 1+x^0<=y^0 ], cost: 1 9: l1 -> l2 : y^0'=z^0, [ 1+x^0<=y^0 && 1+y^0<=z^0 ], cost: 1+2*z^0-2*y^0 1: l2 -> l1 : x^0'=1+x^0, [ z^0<=y^0 ], cost: 1 6: l4 -> l1 : [], cost: 2 Eliminated locations (on tree-shaped paths): Start location: l4 10: l1 -> l1 : x^0'=1+x^0, [ 1+x^0<=y^0 && z^0<=y^0 ], cost: 2 11: l1 -> l1 : x^0'=1+x^0, y^0'=z^0, [ 1+x^0<=y^0 && 1+y^0<=z^0 ], cost: 2+2*z^0-2*y^0 6: l4 -> l1 : [], cost: 2 Accelerating simple loops of location 1. Accelerating the following rules: 10: l1 -> l1 : x^0'=1+x^0, [ 1+x^0<=y^0 && z^0<=y^0 ], cost: 2 11: l1 -> l1 : x^0'=1+x^0, y^0'=z^0, [ 1+x^0<=y^0 && 1+y^0<=z^0 ], cost: 2+2*z^0-2*y^0 Accelerated rule 10 with metering function -x^0+y^0, yielding the new rule 12. Found no metering function for rule 11. Removing the simple loops: 10. Accelerated all simple loops using metering functions (where possible): Start location: l4 11: l1 -> l1 : x^0'=1+x^0, y^0'=z^0, [ 1+x^0<=y^0 && 1+y^0<=z^0 ], cost: 2+2*z^0-2*y^0 12: l1 -> l1 : x^0'=y^0, [ 1+x^0<=y^0 && z^0<=y^0 ], cost: -2*x^0+2*y^0 6: l4 -> l1 : [], cost: 2 Chained accelerated rules (with incoming rules): Start location: l4 6: l4 -> l1 : [], cost: 2 13: l4 -> l1 : x^0'=1+x^0, y^0'=z^0, [ 1+x^0<=y^0 && 1+y^0<=z^0 ], cost: 4+2*z^0-2*y^0 14: l4 -> l1 : x^0'=y^0, [ 1+x^0<=y^0 && z^0<=y^0 ], cost: 2-2*x^0+2*y^0 Removed unreachable locations (and leaf rules with constant cost): Start location: l4 13: l4 -> l1 : x^0'=1+x^0, y^0'=z^0, [ 1+x^0<=y^0 && 1+y^0<=z^0 ], cost: 4+2*z^0-2*y^0 14: l4 -> l1 : x^0'=y^0, [ 1+x^0<=y^0 && z^0<=y^0 ], cost: 2-2*x^0+2*y^0 ### Computing asymptotic complexity ### Fully simplified ITS problem Start location: l4 13: l4 -> l1 : x^0'=1+x^0, y^0'=z^0, [ 1+x^0<=y^0 && 1+y^0<=z^0 ], cost: 4+2*z^0-2*y^0 14: l4 -> l1 : x^0'=y^0, [ 1+x^0<=y^0 && z^0<=y^0 ], cost: 2-2*x^0+2*y^0 Computing asymptotic complexity for rule 13 Solved the limit problem by the following transformations: Created initial limit problem: z^0-y^0 (+/+!), -x^0+y^0 (+/+!), 4+2*z^0-2*y^0 (+) [not solved] removing all constraints (solved by SMT) resulting limit problem: [solved] applying transformation rule (C) using substitution {z^0==n,x^0==0,y^0==1} resulting limit problem: [solved] Solution: z^0 / n x^0 / 0 y^0 / 1 Resulting cost 2+2*n has complexity: Poly(n^1) Found new complexity Poly(n^1). Obtained the following overall complexity (w.r.t. the length of the input n): Complexity: Poly(n^1) Cpx degree: 1 Solved cost: 2+2*n Rule cost: 4+2*z^0-2*y^0 Rule guard: [ 1+x^0<=y^0 && 1+y^0<=z^0 ] WORST_CASE(Omega(n^1),?)