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