WORST_CASE(INF,?) ### 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 metering function y^0, yielding the new rule 8. 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, [ 1<=y^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 && 1<=y^post_4 ], 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 && 1<=y^post_4 ], 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 && 1<=y^post_4 ], cost: 2+2*y^post_4 Accelerated rule 10 with metering function x^0, yielding the new rule 12. Accelerated rule 11 with metering function x^0, yielding the new rule 13. 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, [ 1<=x^0 && y^post_4<=0 ], cost: 2*x^0 13: l2 -> l2 : x^0'=0, y^0'=0, [ 1<=x^0 && 1<=y^post_4 ], cost: 2*x^0*y^post_4+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, [ 1<=x^0 && y^post_4<=0 ], cost: 2+2*x^0 15: l4 -> l2 : x^0'=0, y^0'=0, [ 1<=x^0 && 1<=y^post_4 ], cost: 2+2*x^0*y^post_4+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, [ 1<=x^0 && y^post_4<=0 ], cost: 2+2*x^0 15: l4 -> l2 : x^0'=0, y^0'=0, [ 1<=x^0 && 1<=y^post_4 ], cost: 2+2*x^0*y^post_4+2*x^0 ### Computing asymptotic complexity ### Fully simplified ITS problem Start location: l4 14: l4 -> l2 : x^0'=0, y^0'=y^post_4, [ 1<=x^0 && y^post_4<=0 ], cost: 2+2*x^0 15: l4 -> l2 : x^0'=0, y^0'=0, [ 1<=x^0 && 1<=y^post_4 ], cost: 2+2*x^0*y^post_4+2*x^0 Computing asymptotic complexity for rule 14 Solved the limit problem by the following transformations: Created initial limit problem: 2+2*x^0 (+), 1-y^post_4 (+/+!), x^0 (+/+!) [not solved] removing all constraints (solved by SMT) resulting limit problem: [solved] applying transformation rule (C) using substitution {x^0==n,y^post_4==-n} resulting limit problem: [solved] Solution: x^0 / n y^post_4 / -n Resulting cost 2+2*n has complexity: Poly(n^1) Found new complexity Poly(n^1). Computing asymptotic complexity for rule 15 Solved the limit problem by the following transformations: Created initial limit problem: 2+2*x^0*y^post_4+2*x^0 (+), x^0 (+/+!), y^post_4 (+/+!) [not solved] removing all constraints (solved by SMT) resulting limit problem: [solved] applying transformation rule (C) using substitution {x^0==1,y^post_4==1+n} resulting limit problem: [solved] Solution: x^0 / 1 y^post_4 / 1+n Resulting cost 6+2*n has complexity: Unbounded Found new complexity Unbounded. Obtained the following overall complexity (w.r.t. the length of the input n): Complexity: Unbounded Cpx degree: Unbounded Solved cost: 6+2*n Rule cost: 2+2*x^0*y^post_4+2*x^0 Rule guard: [ 1<=x^0 && 1<=y^post_4 ] WORST_CASE(INF,?)