| ⊦ 0 < i → ¬ i * (i + 1) < 2 |
i * (i + 1) < 2, 0 < i ⊦
| i * (i + 1) < 2, 0 < i ⊦ |
i * i + i < 2, 0 < i ⊦
Used simplifier rules: dist-lsplit: ⊦ (i + i0) * j = i * j + i0 * j; one: ⊦ 1 * i = i; associativity: ⊦ i * j * j0 = (i * j) * j0; commutativity: ⊦ i * j = j * i; forward-le-05: ⊦ i < j ∧ 0 ≤ i → 0 < j; (forward) from specification int-abs add-c: ⊦ i + j = j + i; from specification int-basic2 add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2
| i * i + i < 2, 0 < i ⊦ |
0 < i, i * i + i < 2, ¬ 1 + i * i < 2 ⊦
Used simplifier rules: square-lez-01: ⊦ i * i ≤ 0 ↔ i = 0; associativity: ⊦ i * j * j0 = (i * j) * j0; commutativity: ⊦ i * j = j * i; ⊦ i + (* j) < (* j0) ↔ i < j0 - j; (s) ⊦ i < 1 ↔ i ≤ 0; (s) add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2 add-c: ⊦ i + j = j + i; from specification int-basic2 Used formulas: 1 + i * i < 2
| 0 < i, i * i + i < 2, ¬ 1 + i * i < 2 ⊦ |
⊦ i + j = j + i
i * i + i < 2, 0 < i, ¬ i * i + 1 < 2 ⊦
Used terms: i * i, 1
| i * i + i < 2, 0 < i, ¬ i * i + 1 < 2 ⊦ |
⊦ i + j < i0 ∧ ¬ j < j0 → i + j0 < i0
Used simplifier rules: square-lez-01: ⊦ i * i ≤ 0 ↔ i = 0; associativity: ⊦ i * j * j0 = (i * j) * j0; commutativity: ⊦ i * j = j * i; j0 ≠ 0, j ≤ j0 ⊦ i < (* j) → i < (* j0); (s) ⊦ i ≠ j → (i ≤ j ↔ i < j); (s) ⊦ i < j → ¬ j < i; (s) ⊦ i + (* j) < (* j0) ↔ i < j0 - j; (s) ⊦ i < 1 ↔ i ≤ 0; (s) add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2 add-c: ⊦ i + j = j + i; from specification int-basic2 Used terms: i * i, i, 2, 1
| ⊦ i + j < i0 ∧ ¬ j < j0 → i + j0 < i0 |
The following image shows the proof tree of sequent calculus. The proved goal is at the bottom. You can click on the nodes to view additional rules. See here for details on colors in a proof tree.