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