WORST_CASE(Omega(1),?) ### Pre-processing the ITS problem ### Initial linear ITS problem Start location: l4 0: l0 -> l1 : rt_11^0'=rt_11^post_1, st_14^0'=st_14^post_1, x_13^0'=x_13^post_1, y_15^0'=y_15^post_1, [ rt_11^0==rt_11^post_1 && st_14^0==st_14^post_1 && x_13^0==x_13^post_1 && y_15^0==y_15^post_1 ], cost: 1 1: l1 -> l2 : rt_11^0'=rt_11^post_2, st_14^0'=st_14^post_2, x_13^0'=x_13^post_2, y_15^0'=y_15^post_2, [ x_13^0<=0 && rt_11^post_2==st_14^0 && st_14^0==st_14^post_2 && x_13^0==x_13^post_2 && y_15^0==y_15^post_2 ], cost: 1 2: l1 -> l3 : rt_11^0'=rt_11^post_3, st_14^0'=st_14^post_3, x_13^0'=x_13^post_3, y_15^0'=y_15^post_3, [ 1<=x_13^0 && x_13^post_3==x_13^0+y_15^0 && y_15^post_3==-1+y_15^0 && rt_11^0==rt_11^post_3 && st_14^0==st_14^post_3 ], cost: 1 3: l3 -> l1 : rt_11^0'=rt_11^post_4, st_14^0'=st_14^post_4, x_13^0'=x_13^post_4, y_15^0'=y_15^post_4, [ rt_11^0==rt_11^post_4 && st_14^0==st_14^post_4 && x_13^0==x_13^post_4 && y_15^0==y_15^post_4 ], cost: 1 4: l4 -> l0 : rt_11^0'=rt_11^post_5, st_14^0'=st_14^post_5, x_13^0'=x_13^post_5, y_15^0'=y_15^post_5, [ rt_11^0==rt_11^post_5 && st_14^0==st_14^post_5 && x_13^0==x_13^post_5 && y_15^0==y_15^post_5 ], cost: 1 Checking for constant complexity: The following rule is satisfiable with cost >= 1, yielding constant complexity: 4: l4 -> l0 : rt_11^0'=rt_11^post_5, st_14^0'=st_14^post_5, x_13^0'=x_13^post_5, y_15^0'=y_15^post_5, [ rt_11^0==rt_11^post_5 && st_14^0==st_14^post_5 && x_13^0==x_13^post_5 && y_15^0==y_15^post_5 ], cost: 1 Removed unreachable and leaf rules: Start location: l4 0: l0 -> l1 : rt_11^0'=rt_11^post_1, st_14^0'=st_14^post_1, x_13^0'=x_13^post_1, y_15^0'=y_15^post_1, [ rt_11^0==rt_11^post_1 && st_14^0==st_14^post_1 && x_13^0==x_13^post_1 && y_15^0==y_15^post_1 ], cost: 1 2: l1 -> l3 : rt_11^0'=rt_11^post_3, st_14^0'=st_14^post_3, x_13^0'=x_13^post_3, y_15^0'=y_15^post_3, [ 1<=x_13^0 && x_13^post_3==x_13^0+y_15^0 && y_15^post_3==-1+y_15^0 && rt_11^0==rt_11^post_3 && st_14^0==st_14^post_3 ], cost: 1 3: l3 -> l1 : rt_11^0'=rt_11^post_4, st_14^0'=st_14^post_4, x_13^0'=x_13^post_4, y_15^0'=y_15^post_4, [ rt_11^0==rt_11^post_4 && st_14^0==st_14^post_4 && x_13^0==x_13^post_4 && y_15^0==y_15^post_4 ], cost: 1 4: l4 -> l0 : rt_11^0'=rt_11^post_5, st_14^0'=st_14^post_5, x_13^0'=x_13^post_5, y_15^0'=y_15^post_5, [ rt_11^0==rt_11^post_5 && st_14^0==st_14^post_5 && x_13^0==x_13^post_5 && y_15^0==y_15^post_5 ], cost: 1 Simplified all rules, resulting in: Start location: l4 0: l0 -> l1 : [], cost: 1 2: l1 -> l3 : x_13^0'=x_13^0+y_15^0, y_15^0'=-1+y_15^0, [ 1<=x_13^0 ], cost: 1 3: l3 -> l1 : [], cost: 1 4: l4 -> l0 : [], cost: 1 ### Simplification by acceleration and chaining ### Eliminated locations (on linear paths): Start location: l4 6: l1 -> l1 : x_13^0'=x_13^0+y_15^0, y_15^0'=-1+y_15^0, [ 1<=x_13^0 ], cost: 2 5: l4 -> l1 : [], cost: 2 Accelerating simple loops of location 1. Accelerating the following rules: 6: l1 -> l1 : x_13^0'=x_13^0+y_15^0, y_15^0'=-1+y_15^0, [ 1<=x_13^0 ], cost: 2 [test] deduced pseudo-invariant y_15^0<=0, also trying -y_15^0<=-1 Accelerated rule 6 with backward acceleration, yielding the new rule 7. Accelerated rule 6 with backward acceleration, yielding the new rule 8. [accelerate] Nesting with 2 inner and 1 outer candidates Accelerated all simple loops using metering functions (where possible): Start location: l4 6: l1 -> l1 : x_13^0'=x_13^0+y_15^0, y_15^0'=-1+y_15^0, [ 1<=x_13^0 ], cost: 2 7: l1 -> l1 : x_13^0'=1/2*k+x_13^0-1/2*k^2+k*y_15^0, y_15^0'=-k+y_15^0, [ y_15^0<=0 && k>=0 && 1<=-1/2-1/2*(-1+k)^2+1/2*k+x_13^0+(-1+k)*y_15^0 ], cost: 2*k 8: l1 -> l1 : x_13^0'=x_13^0+1/2*y_15^0^2+1/2*y_15^0, y_15^0'=0, [ 1<=x_13^0 && y_15^0>=0 ], cost: 2*y_15^0 5: l4 -> l1 : [], cost: 2 Chained accelerated rules (with incoming rules): Start location: l4 5: l4 -> l1 : [], cost: 2 9: l4 -> l1 : x_13^0'=x_13^0+y_15^0, y_15^0'=-1+y_15^0, [ 1<=x_13^0 ], cost: 4 10: l4 -> l1 : x_13^0'=1/2*k+x_13^0-1/2*k^2+k*y_15^0, y_15^0'=-k+y_15^0, [ y_15^0<=0 && k>=0 && 1<=-1/2-1/2*(-1+k)^2+1/2*k+x_13^0+(-1+k)*y_15^0 ], cost: 2+2*k 11: l4 -> l1 : x_13^0'=x_13^0+1/2*y_15^0^2+1/2*y_15^0, y_15^0'=0, [ 1<=x_13^0 && y_15^0>=0 ], cost: 2+2*y_15^0 Removed unreachable locations (and leaf rules with constant cost): Start location: l4 10: l4 -> l1 : x_13^0'=1/2*k+x_13^0-1/2*k^2+k*y_15^0, y_15^0'=-k+y_15^0, [ y_15^0<=0 && k>=0 && 1<=-1/2-1/2*(-1+k)^2+1/2*k+x_13^0+(-1+k)*y_15^0 ], cost: 2+2*k 11: l4 -> l1 : x_13^0'=x_13^0+1/2*y_15^0^2+1/2*y_15^0, y_15^0'=0, [ 1<=x_13^0 && y_15^0>=0 ], cost: 2+2*y_15^0 ### Computing asymptotic complexity ### Fully simplified ITS problem Start location: l4 10: l4 -> l1 : x_13^0'=1/2*k+x_13^0-1/2*k^2+k*y_15^0, y_15^0'=-k+y_15^0, [ y_15^0<=0 && k>=0 && 1<=-1/2-1/2*(-1+k)^2+1/2*k+x_13^0+(-1+k)*y_15^0 ], cost: 2+2*k 11: l4 -> l1 : x_13^0'=x_13^0+1/2*y_15^0^2+1/2*y_15^0, y_15^0'=0, [ 1<=x_13^0 && y_15^0>=0 ], cost: 2+2*y_15^0 Computing asymptotic complexity for rule 10 Resulting cost 0 has complexity: Unknown Computing asymptotic complexity for rule 11 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: [ rt_11^0==rt_11^post_5 && st_14^0==st_14^post_5 && x_13^0==x_13^post_5 && y_15^0==y_15^post_5 ] WORST_CASE(Omega(1),?)