unknown Initial ITS Start location: [1] Program variables: x y 0: [1] -> [2] : x'=0, T, cost: 1 1: [2] -> [3] : y'=0, T, cost: 1 2: [3] -> [4] : y >= 0, cost: 1 11: [3] -> [11] : y < 0, cost: 1 3: [4] -> [6] : -50+x <= 0, cost: 1 6: [4] -> [8] : -50+x > 0, cost: 1 9: [5] -> [10] : x'=1+x, T, cost: 1 4: [6] -> [7] : y'=1+y, T, cost: 1 5: [7] -> [5] : T, cost: 1 7: [8] -> [9] : y'=-1+y, T, cost: 1 8: [9] -> [5] : T, cost: 1 10: [10] -> [3] : T, cost: 1 Chained Linear Paths Start location: [1] Program variables: x y 12: [1] -> [3] : x'=0, y'=0, T, cost: 1 2: [3] -> [4] : y >= 0, cost: 1 11: [3] -> [11] : y < 0, cost: 1 15: [4] -> [5] : y'=1+y, -50+x <= 0, cost: 1 16: [4] -> [5] : y'=-1+y, -50+x > 0, cost: 1 17: [5] -> [3] : x'=1+x, T, cost: 1 Eliminating location [2] by chaining: Applied chaining First rule: [1] -> [2] : x'=0, T, cost: 1 Second rule: [2] -> [3] : y'=0, T, cost: 1 New rule: [1] -> [3] : x'=0, y'=0, T, cost: 1 Applied deletion Removed the following rules: 0 1 Eliminating location [6] by chaining: Applied chaining First rule: [4] -> [6] : -50+x <= 0, cost: 1 Second rule: [6] -> [7] : y'=1+y, T, cost: 1 New rule: [4] -> [7] : y'=1+y, -50+x <= 0, cost: 1 Applied deletion Removed the following rules: 3 4 Eliminating location [8] by chaining: Applied chaining First rule: [4] -> [8] : -50+x > 0, cost: 1 Second rule: [8] -> [9] : y'=-1+y, T, cost: 1 New rule: [4] -> [9] : y'=-1+y, -50+x > 0, cost: 1 Applied deletion Removed the following rules: 6 7 Eliminating location [7] by chaining: Applied chaining First rule: [4] -> [7] : y'=1+y, -50+x <= 0, cost: 1 Second rule: [7] -> [5] : T, cost: 1 New rule: [4] -> [5] : y'=1+y, -50+x <= 0, cost: 1 Applied deletion Removed the following rules: 5 13 Eliminating location [9] by chaining: Applied chaining First rule: [4] -> [9] : y'=-1+y, -50+x > 0, cost: 1 Second rule: [9] -> [5] : T, cost: 1 New rule: [4] -> [5] : y'=-1+y, -50+x > 0, cost: 1 Applied deletion Removed the following rules: 8 14 Eliminating location [10] by chaining: Applied chaining First rule: [5] -> [10] : x'=1+x, T, cost: 1 Second rule: [10] -> [3] : T, cost: 1 New rule: [5] -> [3] : x'=1+x, T, cost: 1 Applied deletion Removed the following rules: 9 10 Step with 12 Trace 12[T] Blocked [{}, {}] Step with 2 Trace 12[T], 2[(y >= 0)] Blocked [{}, {11[T]}, {}] Step with 15 Trace 12[T], 2[(y >= 0)], 15[(-50+x <= 0)] Blocked [{}, {11[T]}, {}, {}] Step with 17 Trace 12[T], 2[(y >= 0)], 15[(-50+x <= 0)], 17[T] Blocked [{}, {11[T]}, {}, {}, {}] Accelerate Start location: [1] Program variables: x y 12: [1] -> [3] : x'=0, y'=0, T, cost: 1 2: [3] -> [4] : y >= 0, cost: 1 11: [3] -> [11] : y < 0, cost: 1 18: [3] -> [3] : x'=n+x, y'=n+y, (51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0), cost: 1 15: [4] -> [5] : y'=1+y, -50+x <= 0, cost: 1 16: [4] -> [5] : y'=-1+y, -50+x > 0, cost: 1 17: [5] -> [3] : x'=1+x, T, cost: 1 Loop Acceleration Original rule: [3] -> [3] : x'=1+x, y'=1+y, (-50+x <= 0 /\ y >= 0), cost: 1 New rule: [3] -> [3] : x'=n+x, y'=n+y, (51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0), cost: 1 y >= 0 [0]: monotonic increase yields y >= 0 50-x >= 0 [0]: montonic decrease yields 51-n-x >= 0 50-x >= 0 [1]: eventual increase yields (1 <= 0 /\ 50-x >= 0) Replacement map: {y >= 0 -> y >= 0, 50-x >= 0 -> 51-n-x >= 0} Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)] Blocked [{}, {11[T]}, {18[T]}] Step with 2 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {}] Step with 15 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 15[(-50+x <= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {}, {}] Step with 17 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 15[(-50+x <= 0)], 17[T] Blocked [{}, {11[T]}, {11[T], 18[T]}, {}, {}, {}] Covered Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 15[(-50+x <= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {}, {17[T]}] Backtrack Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {15[T]}] Step with 16 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 16[(-50+x > 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {15[T]}, {}] Step with 17 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 16[(-50+x > 0)], 17[T] Blocked [{}, {11[T]}, {11[T], 18[T]}, {15[T]}, {}, {}] Accelerate Start location: [1] Program variables: x y 12: [1] -> [3] : x'=0, y'=0, T, cost: 1 2: [3] -> [4] : y >= 0, cost: 1 11: [3] -> [11] : y < 0, cost: 1 18: [3] -> [3] : x'=n+x, y'=n+y, (51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0), cost: 1 19: [3] -> [3] : x'=n2+x, y'=-n2+y, (1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0), cost: 1 15: [4] -> [5] : y'=1+y, -50+x <= 0, cost: 1 16: [4] -> [5] : y'=-1+y, -50+x > 0, cost: 1 17: [5] -> [3] : x'=1+x, T, cost: 1 Loop Acceleration Original rule: [3] -> [3] : x'=1+x, y'=-1+y, (-50+x > 0 /\ y >= 0), cost: 1 New rule: [3] -> [3] : x'=n2+x, y'=-n2+y, (1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0), cost: 1 -50+x > 0 [0]: monotonic increase yields -50+x > 0 y >= 0 [0]: montonic decrease yields 1-n2+y >= 0 y >= 0 [1]: eventual increase yields (1 <= 0 /\ y >= 0) Replacement map: {-50+x > 0 -> -50+x > 0, y >= 0 -> 1-n2+y >= 0} Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {19[T]}] Acceleration Failed marked recursive suffix as redundant Step with 11 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)], 11[(y < 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {19[T]}, {}] Backtrack Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {11[T], 19[T]}] Step with 2 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)], 2[(y >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {11[T], 19[T]}, {}] Step with 16 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)], 2[(y >= 0)], 16[(-50+x > 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {11[T], 19[T]}, {}, {}] Step with 17 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)], 2[(y >= 0)], 16[(-50+x > 0)], 17[T] Blocked [{}, {11[T]}, {11[T], 18[T]}, {11[T], 19[T]}, {}, {}, {}] Covered Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)], 2[(y >= 0)], 16[(-50+x > 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {11[T], 19[T]}, {}, {17[T]}] Backtrack Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)], 2[(y >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {11[T], 19[T]}, {16[T]}] Backtrack Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 19[(1-n2+y >= 0 /\ -50+x > 0 /\ -1+n2 >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T]}, {2[T], 11[T], 19[T]}] Backtrack Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}] Step with 2 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {}] Step with 16 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 16[(-50+x > 0)] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {}, {}] Step with 17 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 16[(-50+x > 0)], 17[T] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {}, {}, {}] Covered Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 16[(-50+x > 0)] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {}, {17[T]}] Backtrack Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {16[T]}] Step with 15 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 15[(-50+x <= 0)] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {16[T]}, {}] Step with 17 Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 15[(-50+x <= 0)], 17[T] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {16[T]}, {}, {}] Covered Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)], 15[(-50+x <= 0)] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {16[T]}, {17[T]}] Backtrack Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)], 2[(y >= 0)] Blocked [{}, {11[T]}, {11[T], 18[T], 19[T]}, {15[T], 16[T]}] Backtrack Trace 12[T], 18[(51-n-x >= 0 /\ y >= 0 /\ -1+n >= 0)] Blocked [{}, {11[T]}, {2[T], 11[T], 18[T], 19[T]}] Backtrack Trace 12[T] Blocked [{}, {11[T], 18[T]}] Step with 2 Trace 12[T], 2[(y >= 0)] Blocked [{}, {11[T], 18[T]}, {}] Step with 15 Trace 12[T], 2[(y >= 0)], 15[(-50+x <= 0)] Blocked [{}, {11[T], 18[T]}, {}, {}] Step with 17 Trace 12[T], 2[(y >= 0)], 15[(-50+x <= 0)], 17[T] Blocked [{}, {11[T], 18[T]}, {}, {}, {}] Covered Trace 12[T], 2[(y >= 0)], 15[(-50+x <= 0)] Blocked [{}, {11[T], 18[T]}, {}, {17[T]}] Backtrack Trace 12[T], 2[(y >= 0)] Blocked [{}, {11[T], 18[T]}, {15[T]}] Backtrack Trace 12[T] Blocked [{}, {2[T], 11[T], 18[T]}] Backtrack Trace Blocked [{12[T]}] Accept unknown Build SHA: a05f16bf13df659c382799650051f91bf6828c7b