NO Initial ITS Start location: [1] Program variables: i 0: [1] -> [2] : i'=0, T, cost: 1 1: [2] -> [3] : -100+i < 0, cost: 1 9: [2] -> [9] : -100+i >= 0, cost: 1 2: [3] -> [5] : -50+i < 0, cost: 1 5: [3] -> [7] : -50+i >= 0, cost: 1 8: [4] -> [2] : T, cost: 1 3: [5] -> [6] : i'=51, T, cost: 1 4: [6] -> [4] : T, cost: 1 6: [7] -> [8] : i'=49, T, cost: 1 7: [8] -> [4] : T, cost: 1 Chained Linear Paths Start location: [1] Program variables: i 0: [1] -> [2] : i'=0, T, cost: 1 1: [2] -> [3] : -100+i < 0, cost: 1 9: [2] -> [9] : -100+i >= 0, cost: 1 12: [3] -> [4] : i'=51, -50+i < 0, cost: 1 13: [3] -> [4] : i'=49, -50+i >= 0, cost: 1 8: [4] -> [2] : T, cost: 1 Eliminating location [5] by chaining: Applied chaining First rule: [3] -> [5] : -50+i < 0, cost: 1 Second rule: [5] -> [6] : i'=51, T, cost: 1 New rule: [3] -> [6] : i'=51, -50+i < 0, cost: 1 Applied deletion Removed the following rules: 2 3 Eliminating location [7] by chaining: Applied chaining First rule: [3] -> [7] : -50+i >= 0, cost: 1 Second rule: [7] -> [8] : i'=49, T, cost: 1 New rule: [3] -> [8] : i'=49, -50+i >= 0, cost: 1 Applied deletion Removed the following rules: 5 6 Eliminating location [6] by chaining: Applied chaining First rule: [3] -> [6] : i'=51, -50+i < 0, cost: 1 Second rule: [6] -> [4] : T, cost: 1 New rule: [3] -> [4] : i'=51, -50+i < 0, cost: 1 Applied deletion Removed the following rules: 4 10 Eliminating location [8] by chaining: Applied chaining First rule: [3] -> [8] : i'=49, -50+i >= 0, cost: 1 Second rule: [8] -> [4] : T, cost: 1 New rule: [3] -> [4] : i'=49, -50+i >= 0, cost: 1 Applied deletion Removed the following rules: 7 11 Step with 0 Trace 0[T] Blocked [{}, {}] Step with 1 Trace 0[T], 1[(-100+i < 0)] Blocked [{}, {9[T]}, {}] Step with 12 Trace 0[T], 1[(-100+i < 0)], 12[(-50+i < 0)] Blocked [{}, {9[T]}, {}, {}] Step with 8 Trace 0[T], 1[(-100+i < 0)], 12[(-50+i < 0)], 8[T] Blocked [{}, {9[T]}, {}, {}, {}] Acceleration Failed marked recursive suffix as redundant Step with 1 Trace 0[T], 1[(-100+i < 0)], 12[(-50+i < 0)], 8[T], 1[(-100+i < 0)] Blocked [{}, {9[T]}, {}, {}, {}, {}] Acceleration Failed marked recursive suffix as redundant Step with 13 Trace 0[T], 1[(-100+i < 0)], 12[(-50+i < 0)], 8[T], 1[(-100+i < 0)], 13[(-50+i >= 0)] Blocked [{}, {9[T]}, {}, {}, {}, {12[T]}, {}] Acceleration Failed marked recursive suffix as redundant Step with 8 Trace 0[T], 1[(-100+i < 0)], 12[(-50+i < 0)], 8[T], 1[(-100+i < 0)], 13[(-50+i >= 0)], 8[T] Blocked [{}, {9[T]}, {}, {}, {}, {12[T]}, {}, {}] Acceleration Failed marked recursive suffix as redundant Nonterm Start location: [1] Program variables: i 0: [1] -> [2] : i'=0, T, cost: 1 1: [2] -> [3] : -100+i < 0, cost: 1 9: [2] -> [9] : -100+i >= 0, cost: 1 14: [2] -> LoAT_sink : (100-i > 0 /\ 50-i > 0 /\ -1+n >= 0), cost: NONTERM 12: [3] -> [4] : i'=51, -50+i < 0, cost: 1 13: [3] -> [4] : i'=49, -50+i >= 0, cost: 1 8: [4] -> [2] : T, cost: 1 Certificate of Non-Termination Original rule: [2] -> [2] : i'=49, (-50+i < 0 /\ -100+i < 0), cost: 1 New rule: [2] -> LoAT_sink : (100-i > 0 /\ 50-i > 0 /\ -1+n >= 0), cost: NONTERM 100-i > 0 [0]: monotonic increase yields 100-i > 0 50-i > 0 [0]: monotonic increase yields 50-i > 0 Replacement map: {100-i > 0 -> 100-i > 0, 50-i > 0 -> 50-i > 0} Step with 14 Trace 0[T], 14[(100-i > 0 /\ 50-i > 0 /\ -1+n >= 0)] Blocked [{}, {9[T]}, {14[T]}] Refute Counterexample [ i=0 ] 0 [ i=i ] 14 NO Build SHA: a05f16bf13df659c382799650051f91bf6828c7b