NO Initial ITS Start location: l5 Program variables: nd^0 p^0 x^0 0: l0 -> l1 : nd^0'=nd^post1, p^0'=p^post1, x^0'=x^post1, (nd^0-nd^post1 == 0 /\ nd^0 <= 0 /\ -2+p^post1 == 0 /\ -x^post1+x^0 == 0), cost: 1 1: l0 -> l1 : nd^0'=nd^post2, p^0'=p^post2, x^0'=x^post2, (-1+p^post2 == 0 /\ nd^0-nd^post2 == 0 /\ 1-nd^0 <= 0 /\ -x^post2+x^0 == 0), cost: 1 2: l1 -> l0 : nd^0'=nd^post3, p^0'=p^post3, x^0'=x^post3, (0 == 0 /\ -p^post3+p^0 == 0 /\ -x^post3+x^0 == 0), cost: 1 3: l2 -> l3 : nd^0'=nd^post4, p^0'=p^post4, x^0'=x^post4, (2+x^post4-x^0 == 0 /\ -p^post4+p^0 == 0 /\ nd^0 <= 0 /\ nd^0-nd^post4 == 0), cost: 1 4: l2 -> l3 : nd^0'=nd^post5, p^0'=p^post5, x^0'=x^post5, (1+x^post5-x^0 == 0 /\ p^0-p^post5 == 0 /\ 1-nd^0 <= 0 /\ -nd^post5+nd^0 == 0), cost: 1 5: l3 -> l1 : nd^0'=nd^post6, p^0'=p^post6, x^0'=x^post6, (-nd^post6+nd^0 == 0 /\ p^0-p^post6 == 0 /\ x^0 <= 0 /\ -x^post6+x^0 == 0), cost: 1 6: l3 -> l2 : nd^0'=nd^post7, p^0'=p^post7, x^0'=x^post7, (0 == 0 /\ p^0-p^post7 == 0 /\ 1-x^0 <= 0 /\ -x^post7+x^0 == 0), cost: 1 7: l4 -> l3 : nd^0'=nd^post8, p^0'=p^post8, x^0'=x^post8, (p^post8 == 0 /\ -nd^post8+nd^0 == 0 /\ x^0-x^post8 == 0), cost: 1 8: l5 -> l4 : nd^0'=nd^post9, p^0'=p^post9, x^0'=x^post9, (-nd^post9+nd^0 == 0 /\ p^0-p^post9 == 0 /\ x^0-x^post9 == 0), cost: 1 Chained Linear Paths Start location: l5 Program variables: nd^0 p^0 x^0 0: l0 -> l1 : nd^0'=nd^post1, p^0'=p^post1, x^0'=x^post1, (nd^0-nd^post1 == 0 /\ nd^0 <= 0 /\ -2+p^post1 == 0 /\ -x^post1+x^0 == 0), cost: 1 1: l0 -> l1 : nd^0'=nd^post2, p^0'=p^post2, x^0'=x^post2, (-1+p^post2 == 0 /\ nd^0-nd^post2 == 0 /\ 1-nd^0 <= 0 /\ -x^post2+x^0 == 0), cost: 1 2: l1 -> l0 : nd^0'=nd^post3, p^0'=p^post3, x^0'=x^post3, (0 == 0 /\ -p^post3+p^0 == 0 /\ -x^post3+x^0 == 0), cost: 1 3: l2 -> l3 : nd^0'=nd^post4, p^0'=p^post4, x^0'=x^post4, (2+x^post4-x^0 == 0 /\ -p^post4+p^0 == 0 /\ nd^0 <= 0 /\ nd^0-nd^post4 == 0), cost: 1 4: l2 -> l3 : nd^0'=nd^post5, p^0'=p^post5, x^0'=x^post5, (1+x^post5-x^0 == 0 /\ p^0-p^post5 == 0 /\ 1-nd^0 <= 0 /\ -nd^post5+nd^0 == 0), cost: 1 5: l3 -> l1 : nd^0'=nd^post6, p^0'=p^post6, x^0'=x^post6, (-nd^post6+nd^0 == 0 /\ p^0-p^post6 == 0 /\ x^0 <= 0 /\ -x^post6+x^0 == 0), cost: 1 6: l3 -> l2 : nd^0'=nd^post7, p^0'=p^post7, x^0'=x^post7, (0 == 0 /\ p^0-p^post7 == 0 /\ 1-x^0 <= 0 /\ -x^post7+x^0 == 0), cost: 1 9: l5 -> l3 : nd^0'=nd^post8, p^0'=p^post8, x^0'=x^post8, (-nd^post9+nd^0 == 0 /\ p^post8 == 0 /\ p^0-p^post9 == 0 /\ nd^post9-nd^post8 == 0 /\ x^0-x^post9 == 0 /\ x^post9-x^post8 == 0), cost: 1 Eliminating location l4 by chaining: Applied chaining First rule: l5 -> l4 : nd^0'=nd^post9, p^0'=p^post9, x^0'=x^post9, (-nd^post9+nd^0 == 0 /\ p^0-p^post9 == 0 /\ x^0-x^post9 == 0), cost: 1 Second rule: l4 -> l3 : nd^0'=nd^post8, p^0'=p^post8, x^0'=x^post8, (p^post8 == 0 /\ -nd^post8+nd^0 == 0 /\ x^0-x^post8 == 0), cost: 1 New rule: l5 -> l3 : nd^0'=nd^post8, p^0'=p^post8, x^0'=x^post8, (-nd^post9+nd^0 == 0 /\ p^post8 == 0 /\ p^0-p^post9 == 0 /\ nd^post9-nd^post8 == 0 /\ x^0-x^post9 == 0 /\ x^post9-x^post8 == 0), cost: 1 Applied deletion Removed the following rules: 7 8 Simplified Transitions Start location: l5 Program variables: nd^0 p^0 x^0 10: l0 -> l1 : p^0'=2, nd^0 <= 0, cost: 1 11: l0 -> l1 : p^0'=1, 1-nd^0 <= 0, cost: 1 12: l1 -> l0 : nd^0'=nd^post3, T, cost: 1 13: l2 -> l3 : x^0'=-2+x^0, nd^0 <= 0, cost: 1 14: l2 -> l3 : x^0'=-1+x^0, 1-nd^0 <= 0, cost: 1 15: l3 -> l1 : x^0 <= 0, cost: 1 16: l3 -> l2 : nd^0'=nd^post7, 1-x^0 <= 0, cost: 1 17: l5 -> l3 : p^0'=0, T, cost: 1 Propagated Equalities Original rule: l0 -> l1 : nd^0'=nd^post1, p^0'=p^post1, x^0'=x^post1, (nd^0-nd^post1 == 0 /\ nd^0 <= 0 /\ -2+p^post1 == 0 /\ -x^post1+x^0 == 0), cost: 1 New rule: l0 -> l1 : nd^0'=nd^0, p^0'=2, x^0'=x^0, (0 == 0 /\ nd^0 <= 0), cost: 1 propagated equality nd^post1 = nd^0 propagated equality p^post1 = 2 propagated equality x^post1 = x^0 Simplified Guard Original rule: l0 -> l1 : nd^0'=nd^0, p^0'=2, x^0'=x^0, (0 == 0 /\ nd^0 <= 0), cost: 1 New rule: l0 -> l1 : nd^0'=nd^0, p^0'=2, x^0'=x^0, nd^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l0 -> l1 : nd^0'=nd^0, p^0'=2, x^0'=x^0, nd^0 <= 0, cost: 1 New rule: l0 -> l1 : p^0'=2, nd^0 <= 0, cost: 1 Propagated Equalities Original rule: l0 -> l1 : nd^0'=nd^post2, p^0'=p^post2, x^0'=x^post2, (-1+p^post2 == 0 /\ nd^0-nd^post2 == 0 /\ 1-nd^0 <= 0 /\ -x^post2+x^0 == 0), cost: 1 New rule: l0 -> l1 : nd^0'=nd^0, p^0'=1, x^0'=x^0, (0 == 0 /\ 1-nd^0 <= 0), cost: 1 propagated equality p^post2 = 1 propagated equality nd^post2 = nd^0 propagated equality x^post2 = x^0 Simplified Guard Original rule: l0 -> l1 : nd^0'=nd^0, p^0'=1, x^0'=x^0, (0 == 0 /\ 1-nd^0 <= 0), cost: 1 New rule: l0 -> l1 : nd^0'=nd^0, p^0'=1, x^0'=x^0, 1-nd^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l0 -> l1 : nd^0'=nd^0, p^0'=1, x^0'=x^0, 1-nd^0 <= 0, cost: 1 New rule: l0 -> l1 : p^0'=1, 1-nd^0 <= 0, cost: 1 Propagated Equalities Original rule: l1 -> l0 : nd^0'=nd^post3, p^0'=p^post3, x^0'=x^post3, (0 == 0 /\ -p^post3+p^0 == 0 /\ -x^post3+x^0 == 0), cost: 1 New rule: l1 -> l0 : nd^0'=nd^post3, p^0'=p^0, x^0'=x^0, 0 == 0, cost: 1 propagated equality p^post3 = p^0 propagated equality x^post3 = x^0 Simplified Guard Original rule: l1 -> l0 : nd^0'=nd^post3, p^0'=p^0, x^0'=x^0, 0 == 0, cost: 1 New rule: l1 -> l0 : nd^0'=nd^post3, p^0'=p^0, x^0'=x^0, T, cost: 1 Removed Trivial Updates Original rule: l1 -> l0 : nd^0'=nd^post3, p^0'=p^0, x^0'=x^0, T, cost: 1 New rule: l1 -> l0 : nd^0'=nd^post3, T, cost: 1 Propagated Equalities Original rule: l2 -> l3 : nd^0'=nd^post4, p^0'=p^post4, x^0'=x^post4, (2+x^post4-x^0 == 0 /\ -p^post4+p^0 == 0 /\ nd^0 <= 0 /\ nd^0-nd^post4 == 0), cost: 1 New rule: l2 -> l3 : nd^0'=nd^0, p^0'=p^0, x^0'=-2+x^0, (0 == 0 /\ nd^0 <= 0), cost: 1 propagated equality x^post4 = -2+x^0 propagated equality p^post4 = p^0 propagated equality nd^post4 = nd^0 Simplified Guard Original rule: l2 -> l3 : nd^0'=nd^0, p^0'=p^0, x^0'=-2+x^0, (0 == 0 /\ nd^0 <= 0), cost: 1 New rule: l2 -> l3 : nd^0'=nd^0, p^0'=p^0, x^0'=-2+x^0, nd^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l2 -> l3 : nd^0'=nd^0, p^0'=p^0, x^0'=-2+x^0, nd^0 <= 0, cost: 1 New rule: l2 -> l3 : x^0'=-2+x^0, nd^0 <= 0, cost: 1 Propagated Equalities Original rule: l2 -> l3 : nd^0'=nd^post5, p^0'=p^post5, x^0'=x^post5, (1+x^post5-x^0 == 0 /\ p^0-p^post5 == 0 /\ 1-nd^0 <= 0 /\ -nd^post5+nd^0 == 0), cost: 1 New rule: l2 -> l3 : nd^0'=nd^0, p^0'=p^0, x^0'=-1+x^0, (0 == 0 /\ 1-nd^0 <= 0), cost: 1 propagated equality x^post5 = -1+x^0 propagated equality p^post5 = p^0 propagated equality nd^post5 = nd^0 Simplified Guard Original rule: l2 -> l3 : nd^0'=nd^0, p^0'=p^0, x^0'=-1+x^0, (0 == 0 /\ 1-nd^0 <= 0), cost: 1 New rule: l2 -> l3 : nd^0'=nd^0, p^0'=p^0, x^0'=-1+x^0, 1-nd^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l2 -> l3 : nd^0'=nd^0, p^0'=p^0, x^0'=-1+x^0, 1-nd^0 <= 0, cost: 1 New rule: l2 -> l3 : x^0'=-1+x^0, 1-nd^0 <= 0, cost: 1 Propagated Equalities Original rule: l3 -> l1 : nd^0'=nd^post6, p^0'=p^post6, x^0'=x^post6, (-nd^post6+nd^0 == 0 /\ p^0-p^post6 == 0 /\ x^0 <= 0 /\ -x^post6+x^0 == 0), cost: 1 New rule: l3 -> l1 : nd^0'=nd^0, p^0'=p^0, x^0'=x^0, (0 == 0 /\ x^0 <= 0), cost: 1 propagated equality nd^post6 = nd^0 propagated equality p^post6 = p^0 propagated equality x^post6 = x^0 Simplified Guard Original rule: l3 -> l1 : nd^0'=nd^0, p^0'=p^0, x^0'=x^0, (0 == 0 /\ x^0 <= 0), cost: 1 New rule: l3 -> l1 : nd^0'=nd^0, p^0'=p^0, x^0'=x^0, x^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l3 -> l1 : nd^0'=nd^0, p^0'=p^0, x^0'=x^0, x^0 <= 0, cost: 1 New rule: l3 -> l1 : x^0 <= 0, cost: 1 Propagated Equalities Original rule: l3 -> l2 : nd^0'=nd^post7, p^0'=p^post7, x^0'=x^post7, (0 == 0 /\ p^0-p^post7 == 0 /\ 1-x^0 <= 0 /\ -x^post7+x^0 == 0), cost: 1 New rule: l3 -> l2 : nd^0'=nd^post7, p^0'=p^0, x^0'=x^0, (0 == 0 /\ 1-x^0 <= 0), cost: 1 propagated equality p^post7 = p^0 propagated equality x^post7 = x^0 Simplified Guard Original rule: l3 -> l2 : nd^0'=nd^post7, p^0'=p^0, x^0'=x^0, (0 == 0 /\ 1-x^0 <= 0), cost: 1 New rule: l3 -> l2 : nd^0'=nd^post7, p^0'=p^0, x^0'=x^0, 1-x^0 <= 0, cost: 1 Removed Trivial Updates Original rule: l3 -> l2 : nd^0'=nd^post7, p^0'=p^0, x^0'=x^0, 1-x^0 <= 0, cost: 1 New rule: l3 -> l2 : nd^0'=nd^post7, 1-x^0 <= 0, cost: 1 Propagated Equalities Original rule: l5 -> l3 : nd^0'=nd^post8, p^0'=p^post8, x^0'=x^post8, (-nd^post9+nd^0 == 0 /\ p^post8 == 0 /\ p^0-p^post9 == 0 /\ nd^post9-nd^post8 == 0 /\ x^0-x^post9 == 0 /\ x^post9-x^post8 == 0), cost: 1 New rule: l5 -> l3 : nd^0'=nd^post9, p^0'=0, x^0'=x^post9, (0 == 0 /\ -nd^post9+nd^0 == 0 /\ p^0-p^post9 == 0 /\ x^0-x^post9 == 0), cost: 1 propagated equality p^post8 = 0 propagated equality nd^post8 = nd^post9 propagated equality x^post8 = x^post9 Propagated Equalities Original rule: l5 -> l3 : nd^0'=nd^post9, p^0'=0, x^0'=x^post9, (0 == 0 /\ -nd^post9+nd^0 == 0 /\ p^0-p^post9 == 0 /\ x^0-x^post9 == 0), cost: 1 New rule: l5 -> l3 : nd^0'=nd^0, p^0'=0, x^0'=x^0, 0 == 0, cost: 1 propagated equality nd^post9 = nd^0 propagated equality p^post9 = p^0 propagated equality x^post9 = x^0 Simplified Guard Original rule: l5 -> l3 : nd^0'=nd^0, p^0'=0, x^0'=x^0, 0 == 0, cost: 1 New rule: l5 -> l3 : nd^0'=nd^0, p^0'=0, x^0'=x^0, T, cost: 1 Removed Trivial Updates Original rule: l5 -> l3 : nd^0'=nd^0, p^0'=0, x^0'=x^0, T, cost: 1 New rule: l5 -> l3 : p^0'=0, T, cost: 1 Step with 17 Trace 17[T] Blocked [{}, {}] Step with 15 Trace 17[T], 15[(x^0 <= 0)] Blocked [{}, {}, {}] Step with 12 Trace 17[T], 15[(x^0 <= 0)], 12[T] Blocked [{}, {}, {}, {}] Step with 10 Trace 17[T], 15[(x^0 <= 0)], 12[T], 10[(nd^0 <= 0)] Blocked [{}, {}, {}, {}, {}] Nonterm Start location: l5 Program variables: nd^0 p^0 x^0 10: l0 -> l1 : p^0'=2, nd^0 <= 0, cost: 1 11: l0 -> l1 : p^0'=1, 1-nd^0 <= 0, cost: 1 12: l1 -> l0 : nd^0'=nd^post3, T, cost: 1 18: l1 -> LoAT_sink : (-1+n >= 0 /\ -nd^post31 >= 0), cost: NONTERM 13: l2 -> l3 : x^0'=-2+x^0, nd^0 <= 0, cost: 1 14: l2 -> l3 : x^0'=-1+x^0, 1-nd^0 <= 0, cost: 1 15: l3 -> l1 : x^0 <= 0, cost: 1 16: l3 -> l2 : nd^0'=nd^post7, 1-x^0 <= 0, cost: 1 17: l5 -> l3 : p^0'=0, T, cost: 1 Certificate of Non-Termination Original rule: l1 -> l1 : nd^0'=nd^post31, p^0'=2, nd^post31 <= 0, cost: 1 New rule: l1 -> LoAT_sink : (-1+n >= 0 /\ -nd^post31 >= 0), cost: NONTERM -nd^post31 >= 0 [0]: monotonic increase yields -nd^post31 >= 0 Replacement map: {-nd^post31 >= 0 -> -nd^post31 >= 0} Step with 18 Trace 17[T], 15[(x^0 <= 0)], 18[(-1+n >= 0 /\ -nd^post31 >= 0)] Blocked [{}, {}, {}, {18[T]}] Refute Counterexample [ nd^0=0 p^0=0 x^0=0 ] 17 [ nd^0=0 p^0=0 x^0=0 ] 15 [ nd^0=0 p^0=p^0 x^0=0 ] 18 NO Build SHA: a05f16bf13df659c382799650051f91bf6828c7b