NO Initial ITS Start location: l3 Program variables: __const_200^0 x^0 0: l0 -> l1 : __const_200^0'=__const_200^post1, x^0'=x^post1, (1+__const_200^0-x^post1 <= 0 /\ -1+x^post1-x^0 == 0 /\ -__const_200^post1+__const_200^0 == 0), cost: 1 1: l1 -> l0 : __const_200^0'=__const_200^post2, x^0'=x^post2, (-x^post2+x^0 == 0 /\ __const_200^0-__const_200^post2 == 0), cost: 1 2: l2 -> l0 : __const_200^0'=__const_200^post3, x^0'=x^post3, (__const_200^0-__const_200^post3 == 0 /\ -x^post3+x^0 == 0), cost: 1 3: l3 -> l2 : __const_200^0'=__const_200^post4, x^0'=x^post4, (-x^post4+x^0 == 0 /\ -__const_200^post4+__const_200^0 == 0), cost: 1 Chained Linear Paths Start location: l3 Program variables: __const_200^0 x^0 5: l0 -> l0 : __const_200^0'=__const_200^post2, x^0'=x^post2, (__const_200^post1-__const_200^post2 == 0 /\ 1+__const_200^0-x^post1 <= 0 /\ -1+x^post1-x^0 == 0 /\ -__const_200^post1+__const_200^0 == 0 /\ -x^post2+x^post1 == 0), cost: 1 4: l3 -> l0 : __const_200^0'=__const_200^post3, x^0'=x^post3, (-x^post4+x^0 == 0 /\ x^post4-x^post3 == 0 /\ __const_200^post4-__const_200^post3 == 0 /\ -__const_200^post4+__const_200^0 == 0), cost: 1 Eliminating location l2 by chaining: Applied chaining First rule: l3 -> l2 : __const_200^0'=__const_200^post4, x^0'=x^post4, (-x^post4+x^0 == 0 /\ -__const_200^post4+__const_200^0 == 0), cost: 1 Second rule: l2 -> l0 : __const_200^0'=__const_200^post3, x^0'=x^post3, (__const_200^0-__const_200^post3 == 0 /\ -x^post3+x^0 == 0), cost: 1 New rule: l3 -> l0 : __const_200^0'=__const_200^post3, x^0'=x^post3, (-x^post4+x^0 == 0 /\ x^post4-x^post3 == 0 /\ __const_200^post4-__const_200^post3 == 0 /\ -__const_200^post4+__const_200^0 == 0), cost: 1 Applied deletion Removed the following rules: 2 3 Eliminating location l1 by chaining: Applied chaining First rule: l0 -> l1 : __const_200^0'=__const_200^post1, x^0'=x^post1, (1+__const_200^0-x^post1 <= 0 /\ -1+x^post1-x^0 == 0 /\ -__const_200^post1+__const_200^0 == 0), cost: 1 Second rule: l1 -> l0 : __const_200^0'=__const_200^post2, x^0'=x^post2, (-x^post2+x^0 == 0 /\ __const_200^0-__const_200^post2 == 0), cost: 1 New rule: l0 -> l0 : __const_200^0'=__const_200^post2, x^0'=x^post2, (__const_200^post1-__const_200^post2 == 0 /\ 1+__const_200^0-x^post1 <= 0 /\ -1+x^post1-x^0 == 0 /\ -__const_200^post1+__const_200^0 == 0 /\ -x^post2+x^post1 == 0), cost: 1 Applied deletion Removed the following rules: 0 1 Simplified Transitions Start location: l3 Program variables: __const_200^0 x^0 7: l0 -> l0 : x^0'=1+x^0, __const_200^0-x^0 <= 0, cost: 1 6: l3 -> l0 : T, cost: 1 Propagated Equalities Original rule: l3 -> l0 : __const_200^0'=__const_200^post3, x^0'=x^post3, (-x^post4+x^0 == 0 /\ x^post4-x^post3 == 0 /\ __const_200^post4-__const_200^post3 == 0 /\ -__const_200^post4+__const_200^0 == 0), cost: 1 New rule: l3 -> l0 : __const_200^0'=__const_200^post4, x^0'=x^post4, (0 == 0 /\ -x^post4+x^0 == 0 /\ -__const_200^post4+__const_200^0 == 0), cost: 1 propagated equality x^post3 = x^post4 propagated equality __const_200^post3 = __const_200^post4 Propagated Equalities Original rule: l3 -> l0 : __const_200^0'=__const_200^post4, x^0'=x^post4, (0 == 0 /\ -x^post4+x^0 == 0 /\ -__const_200^post4+__const_200^0 == 0), cost: 1 New rule: l3 -> l0 : __const_200^0'=__const_200^0, x^0'=x^0, 0 == 0, cost: 1 propagated equality x^post4 = x^0 propagated equality __const_200^post4 = __const_200^0 Simplified Guard Original rule: l3 -> l0 : __const_200^0'=__const_200^0, x^0'=x^0, 0 == 0, cost: 1 New rule: l3 -> l0 : __const_200^0'=__const_200^0, x^0'=x^0, T, cost: 1 Removed Trivial Updates Original rule: l3 -> l0 : __const_200^0'=__const_200^0, x^0'=x^0, T, cost: 1 New rule: l3 -> l0 : T, cost: 1 Propagated Equalities Original rule: l0 -> l0 : __const_200^0'=__const_200^post2, x^0'=x^post2, (__const_200^post1-__const_200^post2 == 0 /\ 1+__const_200^0-x^post1 <= 0 /\ -1+x^post1-x^0 == 0 /\ -__const_200^post1+__const_200^0 == 0 /\ -x^post2+x^post1 == 0), cost: 1 New rule: l0 -> l0 : __const_200^0'=__const_200^post1, x^0'=x^post1, (0 == 0 /\ 1+__const_200^0-x^post1 <= 0 /\ -1+x^post1-x^0 == 0 /\ -__const_200^post1+__const_200^0 == 0), cost: 1 propagated equality __const_200^post2 = __const_200^post1 propagated equality x^post2 = x^post1 Propagated Equalities Original rule: l0 -> l0 : __const_200^0'=__const_200^post1, x^0'=x^post1, (0 == 0 /\ 1+__const_200^0-x^post1 <= 0 /\ -1+x^post1-x^0 == 0 /\ -__const_200^post1+__const_200^0 == 0), cost: 1 New rule: l0 -> l0 : __const_200^0'=__const_200^0, x^0'=1+x^0, (0 == 0 /\ __const_200^0-x^0 <= 0), cost: 1 propagated equality x^post1 = 1+x^0 propagated equality __const_200^post1 = __const_200^0 Simplified Guard Original rule: l0 -> l0 : __const_200^0'=__const_200^0, x^0'=1+x^0, (0 == 0 /\ __const_200^0-x^0 <= 0), cost: 1 New rule: l0 -> l0 : __const_200^0'=__const_200^0, x^0'=1+x^0, __const_200^0-x^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l0 -> l0 : __const_200^0'=__const_200^0, x^0'=1+x^0, __const_200^0-x^0 <= 0, cost: 1 New rule: l0 -> l0 : x^0'=1+x^0, __const_200^0-x^0 <= 0, cost: 1 Step with 6 Trace 6[T] Blocked [{}, {}] Step with 7 Trace 6[T], 7[(__const_200^0-x^0 <= 0)] Blocked [{}, {}, {}] Nonterm Start location: l3 Program variables: __const_200^0 x^0 7: l0 -> l0 : x^0'=1+x^0, __const_200^0-x^0 <= 0, cost: 1 8: l0 -> LoAT_sink : (-1+n >= 0 /\ -__const_200^0+x^0 >= 0), cost: NONTERM 9: l0 -> l0 : x^0'=n+x^0, (-1+n >= 0 /\ -__const_200^0+x^0 >= 0), cost: 1 6: l3 -> l0 : T, cost: 1 Certificate of Non-Termination Original rule: l0 -> l0 : x^0'=1+x^0, (__const_200^0-x^0 <= 0), cost: 1 New rule: l0 -> LoAT_sink : (-1+n >= 0 /\ -__const_200^0+x^0 >= 0), cost: NONTERM -__const_200^0+x^0 >= 0 [0]: monotonic increase yields -__const_200^0+x^0 >= 0 Replacement map: {-__const_200^0+x^0 >= 0 -> -__const_200^0+x^0 >= 0} Loop Acceleration Original rule: l0 -> l0 : x^0'=1+x^0, (__const_200^0-x^0 <= 0), cost: 1 New rule: l0 -> l0 : x^0'=n+x^0, (-1+n >= 0 /\ -__const_200^0+x^0 >= 0), cost: 1 -__const_200^0+x^0 >= 0 [0]: monotonic increase yields -__const_200^0+x^0 >= 0 Replacement map: {-__const_200^0+x^0 >= 0 -> -__const_200^0+x^0 >= 0} Step with 8 Trace 6[T], 8[(-1+n >= 0 /\ -__const_200^0+x^0 >= 0)] Blocked [{}, {}, {8[T]}] Refute Counterexample [ __const_200^0=0 x^0=0 ] 6 [ __const_200^0=0 x^0=0 ] 8 NO Build SHA: a05f16bf13df659c382799650051f91bf6828c7b