WORST_CASE(Omega(n^1),?) ### Pre-processing the ITS problem ### Initial linear ITS problem Start location: l3 0: l0 -> l1 : x^0'=x^post_1, y^0'=y^post_1, [ 1<=x^0 && 1<=y^0 && x^0==x^post_1 && y^0==y^post_1 ], cost: 1 1: l1 -> l0 : x^0'=x^post_2, y^0'=y^post_2, [ x^post_2==-1+x^0 && y^0==y^post_2 ], cost: 1 2: l2 -> l1 : x^0'=x^post_3, y^0'=y^post_3, [ y^post_3==-1+y^0 && x^0==x^post_3 ], cost: 1 3: l2 -> l0 : x^0'=x^post_4, y^0'=y^post_4, [ x^0==x^post_4 && y^0==y^post_4 ], cost: 1 4: l3 -> l2 : x^0'=x^post_5, y^0'=y^post_5, [ x^0==x^post_5 && y^0==y^post_5 ], cost: 1 Checking for constant complexity: The following rule is satisfiable with cost >= 1, yielding constant complexity: 4: l3 -> l2 : x^0'=x^post_5, y^0'=y^post_5, [ x^0==x^post_5 && y^0==y^post_5 ], cost: 1 Simplified all rules, resulting in: Start location: l3 0: l0 -> l1 : [ 1<=x^0 && 1<=y^0 ], cost: 1 1: l1 -> l0 : x^0'=-1+x^0, [], cost: 1 2: l2 -> l1 : y^0'=-1+y^0, [], cost: 1 3: l2 -> l0 : [], cost: 1 4: l3 -> l2 : [], cost: 1 ### Simplification by acceleration and chaining ### Eliminated locations (on tree-shaped paths): Start location: l3 0: l0 -> l1 : [ 1<=x^0 && 1<=y^0 ], cost: 1 1: l1 -> l0 : x^0'=-1+x^0, [], cost: 1 5: l3 -> l1 : y^0'=-1+y^0, [], cost: 2 6: l3 -> l0 : [], cost: 2 Eliminated location l0 (as a last resort): Start location: l3 7: l1 -> l1 : x^0'=-1+x^0, [ 1<=-1+x^0 && 1<=y^0 ], cost: 2 5: l3 -> l1 : y^0'=-1+y^0, [], cost: 2 8: l3 -> l1 : [ 1<=x^0 && 1<=y^0 ], cost: 3 Accelerating simple loops of location 1. Accelerating the following rules: 7: l1 -> l1 : x^0'=-1+x^0, [ 1<=-1+x^0 && 1<=y^0 ], cost: 2 Accelerated rule 7 with metering function -1+x^0, yielding the new rule 9. Removing the simple loops: 7. Accelerated all simple loops using metering functions (where possible): Start location: l3 9: l1 -> l1 : x^0'=1, [ 1<=-1+x^0 && 1<=y^0 ], cost: -2+2*x^0 5: l3 -> l1 : y^0'=-1+y^0, [], cost: 2 8: l3 -> l1 : [ 1<=x^0 && 1<=y^0 ], cost: 3 Chained accelerated rules (with incoming rules): Start location: l3 5: l3 -> l1 : y^0'=-1+y^0, [], cost: 2 8: l3 -> l1 : [ 1<=x^0 && 1<=y^0 ], cost: 3 10: l3 -> l1 : x^0'=1, y^0'=-1+y^0, [ 1<=-1+x^0 && 1<=-1+y^0 ], cost: 2*x^0 11: l3 -> l1 : x^0'=1, [ 1<=y^0 && 1<=-1+x^0 ], cost: 1+2*x^0 Removed unreachable locations (and leaf rules with constant cost): Start location: l3 10: l3 -> l1 : x^0'=1, y^0'=-1+y^0, [ 1<=-1+x^0 && 1<=-1+y^0 ], cost: 2*x^0 11: l3 -> l1 : x^0'=1, [ 1<=y^0 && 1<=-1+x^0 ], cost: 1+2*x^0 ### Computing asymptotic complexity ### Fully simplified ITS problem Start location: l3 10: l3 -> l1 : x^0'=1, y^0'=-1+y^0, [ 1<=-1+x^0 && 1<=-1+y^0 ], cost: 2*x^0 11: l3 -> l1 : x^0'=1, [ 1<=y^0 && 1<=-1+x^0 ], cost: 1+2*x^0 Computing asymptotic complexity for rule 10 Solved the limit problem by the following transformations: Created initial limit problem: -1+y^0 (+/+!), -1+x^0 (+/+!), 2*x^0 (+) [not solved] removing all constraints (solved by SMT) resulting limit problem: [solved] applying transformation rule (C) using substitution {x^0==n,y^0==2} resulting limit problem: [solved] Solution: x^0 / n y^0 / 2 Resulting cost 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*n Rule cost: 2*x^0 Rule guard: [ 1<=-1+x^0 && 1<=-1+y^0 ] WORST_CASE(Omega(n^1),?)