WORST_CASE(Omega(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, [ 1<=y^0 && y^post_1==-1+y^0 && x^0==x^post_1 ], cost: 1 2: l0 -> l2 : x^0'=x^post_3, y^0'=y^post_3, [ y^0<=0 && x^0==x^post_3 && y^0==y^post_3 ], cost: 1 1: l1 -> l0 : x^0'=x^post_2, y^0'=y^post_2, [ x^0==x^post_2 && y^0==y^post_2 ], cost: 1 3: l2 -> l0 : x^0'=x^post_4, y^0'=y^post_4, [ 1<=x^0 && x^post_4==-1+x^0 && y^post_4==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 5: l4 -> l3 : x^0'=x^post_6, y^0'=y^post_6, [ x^0==x^post_6 && y^0==y^post_6 ], cost: 1 Checking for constant complexity: The following rule is satisfiable with cost >= 1, yielding constant complexity: 5: l4 -> l3 : x^0'=x^post_6, y^0'=y^post_6, [ x^0==x^post_6 && y^0==y^post_6 ], cost: 1 Simplified all rules, resulting in: Start location: l4 0: l0 -> l1 : y^0'=-1+y^0, [ 1<=y^0 ], cost: 1 2: l0 -> l2 : [ y^0<=0 ], cost: 1 1: l1 -> l0 : [], cost: 1 3: l2 -> l0 : x^0'=-1+x^0, y^0'=y^post_4, [ 1<=x^0 ], cost: 1 4: l3 -> l2 : [], cost: 1 5: l4 -> l3 : [], cost: 1 ### Simplification by acceleration and chaining ### Eliminated locations (on linear paths): Start location: l4 2: l0 -> l2 : [ y^0<=0 ], cost: 1 7: l0 -> l0 : y^0'=-1+y^0, [ 1<=y^0 ], cost: 2 3: l2 -> l0 : x^0'=-1+x^0, y^0'=y^post_4, [ 1<=x^0 ], cost: 1 6: l4 -> l2 : [], cost: 2 Accelerating simple loops of location 0. Accelerating the following rules: 7: l0 -> l0 : y^0'=-1+y^0, [ 1<=y^0 ], cost: 2 Accelerated rule 7 with backward acceleration, yielding the new rule 8. [accelerate] Nesting with 1 inner and 1 outer candidates Removing the simple loops: 7. Accelerated all simple loops using metering functions (where possible): Start location: l4 2: l0 -> l2 : [ y^0<=0 ], cost: 1 8: l0 -> l0 : y^0'=0, [ y^0>=0 ], cost: 2*y^0 3: l2 -> l0 : x^0'=-1+x^0, y^0'=y^post_4, [ 1<=x^0 ], cost: 1 6: l4 -> l2 : [], cost: 2 Chained accelerated rules (with incoming rules): Start location: l4 2: l0 -> l2 : [ y^0<=0 ], cost: 1 3: l2 -> l0 : x^0'=-1+x^0, y^0'=y^post_4, [ 1<=x^0 ], cost: 1 9: l2 -> l0 : x^0'=-1+x^0, y^0'=0, [ 1<=x^0 && y^post_4>=0 ], cost: 1+2*y^post_4 6: l4 -> l2 : [], cost: 2 Eliminated locations (on tree-shaped paths): Start location: l4 10: l2 -> l2 : x^0'=-1+x^0, y^0'=y^post_4, [ 1<=x^0 && y^post_4<=0 ], cost: 2 11: l2 -> l2 : x^0'=-1+x^0, y^0'=0, [ 1<=x^0 && y^post_4>=0 ], cost: 2+2*y^post_4 6: l4 -> l2 : [], cost: 2 Accelerating simple loops of location 2. Accelerating the following rules: 10: l2 -> l2 : x^0'=-1+x^0, y^0'=y^post_4, [ 1<=x^0 && y^post_4<=0 ], cost: 2 11: l2 -> l2 : x^0'=-1+x^0, y^0'=0, [ 1<=x^0 && y^post_4>=0 ], cost: 2+2*y^post_4 Accelerated rule 10 with backward acceleration, yielding the new rule 12. Accelerated rule 11 with backward acceleration, yielding the new rule 13. [accelerate] Nesting with 2 inner and 2 outer candidates Removing the simple loops: 10 11. Accelerated all simple loops using metering functions (where possible): Start location: l4 12: l2 -> l2 : x^0'=0, y^0'=y^post_4, [ y^post_4<=0 && x^0>=1 ], cost: 2*x^0 13: l2 -> l2 : x^0'=0, y^0'=0, [ y^post_4>=0 && x^0>=1 ], cost: 2*y^post_4*x^0+2*x^0 6: l4 -> l2 : [], cost: 2 Chained accelerated rules (with incoming rules): Start location: l4 6: l4 -> l2 : [], cost: 2 14: l4 -> l2 : x^0'=0, y^0'=y^post_4, [ y^post_4<=0 && x^0>=1 ], cost: 2+2*x^0 15: l4 -> l2 : x^0'=0, y^0'=0, [ y^post_4>=0 && x^0>=1 ], cost: 2+2*y^post_4*x^0+2*x^0 Removed unreachable locations (and leaf rules with constant cost): Start location: l4 14: l4 -> l2 : x^0'=0, y^0'=y^post_4, [ y^post_4<=0 && x^0>=1 ], cost: 2+2*x^0 15: l4 -> l2 : x^0'=0, y^0'=0, [ y^post_4>=0 && x^0>=1 ], cost: 2+2*y^post_4*x^0+2*x^0 ### Computing asymptotic complexity ### Fully simplified ITS problem Start location: l4 14: l4 -> l2 : x^0'=0, y^0'=y^post_4, [ y^post_4<=0 && x^0>=1 ], cost: 2+2*x^0 15: l4 -> l2 : x^0'=0, y^0'=0, [ y^post_4>=0 && x^0>=1 ], cost: 2+2*y^post_4*x^0+2*x^0 Computing asymptotic complexity for rule 15 Resulting cost 0 has complexity: Unknown Computing asymptotic complexity for rule 14 Resulting cost 0 has complexity: Unknown Obtained the following overall complexity (w.r.t. the length of the input n): Complexity: Constant Cpx degree: 0 Solved cost: 1 Rule cost: 1 Rule guard: [ x^0==x^post_6 && y^0==y^post_6 ] WORST_CASE(Omega(1),?)