NO Initial ITS Start location: l4 Program variables: result_4^0 x_5^0 0: l0 -> l1 : result_4^0'=result_4^post1, x_5^0'=x_5^post1, (x_5^0-x_5^post1 == 0 /\ -result_4^post1+result_4^0 == 0), cost: 1 1: l1 -> l2 : result_4^0'=result_4^post2, x_5^0'=x_5^post2, (x_5^post2 <= 0 /\ result_4^0-result_4^post2 == 0 /\ 1+x_5^post2-x_5^0 == 0), cost: 1 3: l1 -> l3 : result_4^0'=result_4^post4, x_5^0'=x_5^post4, (0 == 0 /\ 1-x_5^post4 <= 0 /\ 1-x_5^0+x_5^post4 == 0), cost: 1 2: l2 -> l1 : result_4^0'=result_4^post3, x_5^0'=x_5^post3, (-result_4^post3+result_4^0 == 0 /\ x_5^0-x_5^post3 == 0), cost: 1 4: l4 -> l0 : result_4^0'=result_4^post5, x_5^0'=x_5^post5, (result_4^0-result_4^post5 == 0 /\ -x_5^post5+x_5^0 == 0), cost: 1 Chained Linear Paths Start location: l4 Program variables: result_4^0 x_5^0 3: l1 -> l3 : result_4^0'=result_4^post4, x_5^0'=x_5^post4, (0 == 0 /\ 1-x_5^post4 <= 0 /\ 1-x_5^0+x_5^post4 == 0), cost: 1 6: l1 -> l1 : result_4^0'=result_4^post3, x_5^0'=x_5^post3, (x_5^post2 <= 0 /\ -result_4^post3+result_4^post2 == 0 /\ result_4^0-result_4^post2 == 0 /\ x_5^post2-x_5^post3 == 0 /\ 1+x_5^post2-x_5^0 == 0), cost: 1 5: l4 -> l1 : result_4^0'=result_4^post1, x_5^0'=x_5^post1, (x_5^post5-x_5^post1 == 0 /\ result_4^0-result_4^post5 == 0 /\ -result_4^post1+result_4^post5 == 0 /\ -x_5^post5+x_5^0 == 0), cost: 1 Eliminating location l0 by chaining: Applied chaining First rule: l4 -> l0 : result_4^0'=result_4^post5, x_5^0'=x_5^post5, (result_4^0-result_4^post5 == 0 /\ -x_5^post5+x_5^0 == 0), cost: 1 Second rule: l0 -> l1 : result_4^0'=result_4^post1, x_5^0'=x_5^post1, (x_5^0-x_5^post1 == 0 /\ -result_4^post1+result_4^0 == 0), cost: 1 New rule: l4 -> l1 : result_4^0'=result_4^post1, x_5^0'=x_5^post1, (x_5^post5-x_5^post1 == 0 /\ result_4^0-result_4^post5 == 0 /\ -result_4^post1+result_4^post5 == 0 /\ -x_5^post5+x_5^0 == 0), cost: 1 Applied deletion Removed the following rules: 0 4 Eliminating location l2 by chaining: Applied chaining First rule: l1 -> l2 : result_4^0'=result_4^post2, x_5^0'=x_5^post2, (x_5^post2 <= 0 /\ result_4^0-result_4^post2 == 0 /\ 1+x_5^post2-x_5^0 == 0), cost: 1 Second rule: l2 -> l1 : result_4^0'=result_4^post3, x_5^0'=x_5^post3, (-result_4^post3+result_4^0 == 0 /\ x_5^0-x_5^post3 == 0), cost: 1 New rule: l1 -> l1 : result_4^0'=result_4^post3, x_5^0'=x_5^post3, (x_5^post2 <= 0 /\ -result_4^post3+result_4^post2 == 0 /\ result_4^0-result_4^post2 == 0 /\ x_5^post2-x_5^post3 == 0 /\ 1+x_5^post2-x_5^0 == 0), cost: 1 Applied deletion Removed the following rules: 1 2 Simplified Transitions Start location: l4 Program variables: result_4^0 x_5^0 7: l1 -> l3 : result_4^0'=result_4^post4, x_5^0'=-1+x_5^0, 2-x_5^0 <= 0, cost: 1 9: l1 -> l1 : x_5^0'=-1+x_5^0, -1+x_5^0 <= 0, cost: 1 8: l4 -> l1 : T, cost: 1 Propagated Equalities Original rule: l1 -> l3 : result_4^0'=result_4^post4, x_5^0'=x_5^post4, (0 == 0 /\ 1-x_5^post4 <= 0 /\ 1-x_5^0+x_5^post4 == 0), cost: 1 New rule: l1 -> l3 : result_4^0'=result_4^post4, x_5^0'=-1+x_5^0, (0 == 0 /\ 2-x_5^0 <= 0), cost: 1 propagated equality x_5^post4 = -1+x_5^0 Simplified Guard Original rule: l1 -> l3 : result_4^0'=result_4^post4, x_5^0'=-1+x_5^0, (0 == 0 /\ 2-x_5^0 <= 0), cost: 1 New rule: l1 -> l3 : result_4^0'=result_4^post4, x_5^0'=-1+x_5^0, 2-x_5^0 <= 0, cost: 1 Propagated Equalities Original rule: l4 -> l1 : result_4^0'=result_4^post1, x_5^0'=x_5^post1, (x_5^post5-x_5^post1 == 0 /\ result_4^0-result_4^post5 == 0 /\ -result_4^post1+result_4^post5 == 0 /\ -x_5^post5+x_5^0 == 0), cost: 1 New rule: l4 -> l1 : result_4^0'=result_4^post5, x_5^0'=x_5^post5, (0 == 0 /\ result_4^0-result_4^post5 == 0 /\ -x_5^post5+x_5^0 == 0), cost: 1 propagated equality x_5^post1 = x_5^post5 propagated equality result_4^post1 = result_4^post5 Propagated Equalities Original rule: l4 -> l1 : result_4^0'=result_4^post5, x_5^0'=x_5^post5, (0 == 0 /\ result_4^0-result_4^post5 == 0 /\ -x_5^post5+x_5^0 == 0), cost: 1 New rule: l4 -> l1 : result_4^0'=result_4^0, x_5^0'=x_5^0, 0 == 0, cost: 1 propagated equality result_4^post5 = result_4^0 propagated equality x_5^post5 = x_5^0 Simplified Guard Original rule: l4 -> l1 : result_4^0'=result_4^0, x_5^0'=x_5^0, 0 == 0, cost: 1 New rule: l4 -> l1 : result_4^0'=result_4^0, x_5^0'=x_5^0, T, cost: 1 Removed Trivial Updates Original rule: l4 -> l1 : result_4^0'=result_4^0, x_5^0'=x_5^0, T, cost: 1 New rule: l4 -> l1 : T, cost: 1 Propagated Equalities Original rule: l1 -> l1 : result_4^0'=result_4^post3, x_5^0'=x_5^post3, (x_5^post2 <= 0 /\ -result_4^post3+result_4^post2 == 0 /\ result_4^0-result_4^post2 == 0 /\ x_5^post2-x_5^post3 == 0 /\ 1+x_5^post2-x_5^0 == 0), cost: 1 New rule: l1 -> l1 : result_4^0'=result_4^post2, x_5^0'=x_5^post2, (0 == 0 /\ x_5^post2 <= 0 /\ result_4^0-result_4^post2 == 0 /\ 1+x_5^post2-x_5^0 == 0), cost: 1 propagated equality result_4^post3 = result_4^post2 propagated equality x_5^post3 = x_5^post2 Propagated Equalities Original rule: l1 -> l1 : result_4^0'=result_4^post2, x_5^0'=x_5^post2, (0 == 0 /\ x_5^post2 <= 0 /\ result_4^0-result_4^post2 == 0 /\ 1+x_5^post2-x_5^0 == 0), cost: 1 New rule: l1 -> l1 : result_4^0'=result_4^0, x_5^0'=-1+x_5^0, (0 == 0 /\ -1+x_5^0 <= 0), cost: 1 propagated equality result_4^post2 = result_4^0 propagated equality x_5^post2 = -1+x_5^0 Simplified Guard Original rule: l1 -> l1 : result_4^0'=result_4^0, x_5^0'=-1+x_5^0, (0 == 0 /\ -1+x_5^0 <= 0), cost: 1 New rule: l1 -> l1 : result_4^0'=result_4^0, x_5^0'=-1+x_5^0, -1+x_5^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l1 -> l1 : result_4^0'=result_4^0, x_5^0'=-1+x_5^0, -1+x_5^0 <= 0, cost: 1 New rule: l1 -> l1 : x_5^0'=-1+x_5^0, -1+x_5^0 <= 0, cost: 1 Step with 8 Trace 8[T] Blocked [{}, {}] Step with 7 Trace 8[T], 7[(2-x_5^0 <= 0)] Blocked [{}, {}, {}] Backtrack Trace 8[T] Blocked [{}, {7[T]}] Step with 9 Trace 8[T], 9[(-1+x_5^0 <= 0)] Blocked [{}, {7[T]}, {}] Nonterm Start location: l4 Program variables: result_4^0 x_5^0 7: l1 -> l3 : result_4^0'=result_4^post4, x_5^0'=-1+x_5^0, 2-x_5^0 <= 0, cost: 1 9: l1 -> l1 : x_5^0'=-1+x_5^0, -1+x_5^0 <= 0, cost: 1 10: l1 -> LoAT_sink : (-1+n >= 0 /\ 1-x_5^0 >= 0), cost: NONTERM 11: l1 -> l1 : x_5^0'=x_5^0-n, (-1+n >= 0 /\ 1-x_5^0 >= 0), cost: 1 8: l4 -> l1 : T, cost: 1 Certificate of Non-Termination Original rule: l1 -> l1 : x_5^0'=-1+x_5^0, (-1+x_5^0 <= 0), cost: 1 New rule: l1 -> LoAT_sink : (-1+n >= 0 /\ 1-x_5^0 >= 0), cost: NONTERM 1-x_5^0 >= 0 [0]: monotonic increase yields 1-x_5^0 >= 0 Replacement map: {1-x_5^0 >= 0 -> 1-x_5^0 >= 0} Loop Acceleration Original rule: l1 -> l1 : x_5^0'=-1+x_5^0, (-1+x_5^0 <= 0), cost: 1 New rule: l1 -> l1 : x_5^0'=x_5^0-n, (-1+n >= 0 /\ 1-x_5^0 >= 0), cost: 1 1-x_5^0 >= 0 [0]: monotonic increase yields 1-x_5^0 >= 0 Replacement map: {1-x_5^0 >= 0 -> 1-x_5^0 >= 0} Step with 10 Trace 8[T], 10[(-1+n >= 0 /\ 1-x_5^0 >= 0)] Blocked [{}, {7[T]}, {10[T]}] Refute Counterexample [ result_4^0=0 x_5^0=1 ] 8 [ result_4^0=0 x_5^0=1 ] 10 NO Build SHA: a05f16bf13df659c382799650051f91bf6828c7b