| i < 0 ⊦ i→n(i) = (* m) ↔ ~ i = n→i(m) |
¬(i→n(i) = m ↔ ~ i = n→i(m)), i < 0 ⊦
| ¬(i→n(i) = m ↔ ~ i = n→i(m)), i < 0 ⊦ |
i + n→i(m) = 0, i→n(i) ≠ m, i < 0 ⊦
Used simplifier rules: i2i-neg: ⊦ i < 0 → n→i(i→n(i)) = ~ i; ⊦ i < 0 ∧ 0 ≤ j → i < j; (s) forward-le-02: ⊦ j < i ∧ i ≤ 0 → j < 0; (forward) from specification int-abs ⊦ ~ i = j ↔ i + j = 0; (s) ⊦ ~ i = ~ j ↔ i = j; (s)
| i + n→i(m) = 0, i→n(i) ≠ m, i < 0 ⊦ |
Used simplifier rules: abs-neg: ⊦ i→n(~ i) = i→n(i); n2n: ⊦ i→n(n→i(n)) = n; ⊦ ~ i = j ↔ i + j = 0; (s) add-c: ⊦ i + j = j + i; from specification int-basic2 ⊦ ~ i + i = 0; (s) add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2 Used formulas: i = ~ n→i(m)
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.