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_15^0'=x_15^post_1, y_13^0'=y_13^post_1, [ 1+y_13^0<=1 && rt_11^post_1==st_14^0 && st_14^0==st_14^post_1 && x_15^0==x_15^post_1 && y_13^0==y_13^post_1 ], cost: 1 1: l0 -> l2 : rt_11^0'=rt_11^post_2, st_14^0'=st_14^post_2, x_15^0'=x_15^post_2, y_13^0'=y_13^post_2, [ 1<=y_13^0 && rt_11^0==rt_11^post_2 && st_14^0==st_14^post_2 && x_15^0==x_15^post_2 && y_13^0==y_13^post_2 ], cost: 1 2: l2 -> l1 : rt_11^0'=rt_11^post_3, st_14^0'=st_14^post_3, x_15^0'=x_15^post_3, y_13^0'=y_13^post_3, [ x_15^0<=0 && rt_11^post_3==st_14^0 && st_14^0==st_14^post_3 && x_15^0==x_15^post_3 && y_13^0==y_13^post_3 ], cost: 1 3: l2 -> l3 : rt_11^0'=rt_11^post_4, st_14^0'=st_14^post_4, x_15^0'=x_15^post_4, y_13^0'=y_13^post_4, [ 1<=x_15^0 && x_15^post_4==x_15^0-y_13^0 && y_13^post_4==1+y_13^0 && rt_11^0==rt_11^post_4 && st_14^0==st_14^post_4 ], cost: 1 4: l3 -> l2 : rt_11^0'=rt_11^post_5, st_14^0'=st_14^post_5, x_15^0'=x_15^post_5, y_13^0'=y_13^post_5, [ rt_11^0==rt_11^post_5 && st_14^0==st_14^post_5 && x_15^0==x_15^post_5 && y_13^0==y_13^post_5 ], cost: 1 5: l4 -> l0 : rt_11^0'=rt_11^post_6, st_14^0'=st_14^post_6, x_15^0'=x_15^post_6, y_13^0'=y_13^post_6, [ rt_11^0==rt_11^post_6 && st_14^0==st_14^post_6 && x_15^0==x_15^post_6 && y_13^0==y_13^post_6 ], cost: 1 Checking for constant complexity: The following rule is satisfiable with cost >= 1, yielding constant complexity: 5: l4 -> l0 : rt_11^0'=rt_11^post_6, st_14^0'=st_14^post_6, x_15^0'=x_15^post_6, y_13^0'=y_13^post_6, [ rt_11^0==rt_11^post_6 && st_14^0==st_14^post_6 && x_15^0==x_15^post_6 && y_13^0==y_13^post_6 ], cost: 1 Removed unreachable and leaf rules: Start location: l4 1: l0 -> l2 : rt_11^0'=rt_11^post_2, st_14^0'=st_14^post_2, x_15^0'=x_15^post_2, y_13^0'=y_13^post_2, [ 1<=y_13^0 && rt_11^0==rt_11^post_2 && st_14^0==st_14^post_2 && x_15^0==x_15^post_2 && y_13^0==y_13^post_2 ], cost: 1 3: l2 -> l3 : rt_11^0'=rt_11^post_4, st_14^0'=st_14^post_4, x_15^0'=x_15^post_4, y_13^0'=y_13^post_4, [ 1<=x_15^0 && x_15^post_4==x_15^0-y_13^0 && y_13^post_4==1+y_13^0 && rt_11^0==rt_11^post_4 && st_14^0==st_14^post_4 ], cost: 1 4: l3 -> l2 : rt_11^0'=rt_11^post_5, st_14^0'=st_14^post_5, x_15^0'=x_15^post_5, y_13^0'=y_13^post_5, [ rt_11^0==rt_11^post_5 && st_14^0==st_14^post_5 && x_15^0==x_15^post_5 && y_13^0==y_13^post_5 ], cost: 1 5: l4 -> l0 : rt_11^0'=rt_11^post_6, st_14^0'=st_14^post_6, x_15^0'=x_15^post_6, y_13^0'=y_13^post_6, [ rt_11^0==rt_11^post_6 && st_14^0==st_14^post_6 && x_15^0==x_15^post_6 && y_13^0==y_13^post_6 ], cost: 1 Simplified all rules, resulting in: Start location: l4 1: l0 -> l2 : [ 1<=y_13^0 ], cost: 1 3: l2 -> l3 : x_15^0'=x_15^0-y_13^0, y_13^0'=1+y_13^0, [ 1<=x_15^0 ], cost: 1 4: l3 -> l2 : [], cost: 1 5: l4 -> l0 : [], cost: 1 ### Simplification by acceleration and chaining ### Eliminated locations (on linear paths): Start location: l4 7: l2 -> l2 : x_15^0'=x_15^0-y_13^0, y_13^0'=1+y_13^0, [ 1<=x_15^0 ], cost: 2 6: l4 -> l2 : [ 1<=y_13^0 ], cost: 2 Accelerating simple loops of location 2. Accelerating the following rules: 7: l2 -> l2 : x_15^0'=x_15^0-y_13^0, y_13^0'=1+y_13^0, [ 1<=x_15^0 ], cost: 2 [test] deduced invariant 1-y_13^0<=0 Accelerated rule 7 with backward acceleration, yielding the new rule 8. [accelerate] Nesting with 1 inner and 1 outer candidates Accelerated all simple loops using metering functions (where possible): Start location: l4 7: l2 -> l2 : x_15^0'=x_15^0-y_13^0, y_13^0'=1+y_13^0, [ 1<=x_15^0 ], cost: 2 8: l2 -> l2 : x_15^0'=-1/2*k^2+x_15^0-k*y_13^0+1/2*k, y_13^0'=k+y_13^0, [ 1-y_13^0<=0 && k>=0 && 1<=-1/2-1/2*(-1+k)^2-(-1+k)*y_13^0+x_15^0+1/2*k ], cost: 2*k 6: l4 -> l2 : [ 1<=y_13^0 ], cost: 2 Chained accelerated rules (with incoming rules): Start location: l4 6: l4 -> l2 : [ 1<=y_13^0 ], cost: 2 9: l4 -> l2 : x_15^0'=x_15^0-y_13^0, y_13^0'=1+y_13^0, [ 1<=y_13^0 && 1<=x_15^0 ], cost: 4 10: l4 -> l2 : x_15^0'=-1/2*k^2+x_15^0-k*y_13^0+1/2*k, y_13^0'=k+y_13^0, [ 1<=y_13^0 && k>=0 && 1<=-1/2-1/2*(-1+k)^2-(-1+k)*y_13^0+x_15^0+1/2*k ], cost: 2+2*k Removed unreachable locations (and leaf rules with constant cost): Start location: l4 10: l4 -> l2 : x_15^0'=-1/2*k^2+x_15^0-k*y_13^0+1/2*k, y_13^0'=k+y_13^0, [ 1<=y_13^0 && k>=0 && 1<=-1/2-1/2*(-1+k)^2-(-1+k)*y_13^0+x_15^0+1/2*k ], cost: 2+2*k ### Computing asymptotic complexity ### Fully simplified ITS problem Start location: l4 10: l4 -> l2 : x_15^0'=-1/2*k^2+x_15^0-k*y_13^0+1/2*k, y_13^0'=k+y_13^0, [ 1<=y_13^0 && k>=0 && 1<=-1/2-1/2*(-1+k)^2-(-1+k)*y_13^0+x_15^0+1/2*k ], cost: 2+2*k Computing asymptotic complexity for rule 10 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_6 && st_14^0==st_14^post_6 && x_15^0==x_15^post_6 && y_13^0==y_13^post_6 ] WORST_CASE(Omega(1),?)