| n0 + n < # buf, isempty(buf, n0, n), ∀ n2. n0 ≤ n2 ∧ n2 < n0 + n → buf[n2] = empty ⊦ buf[n0 + n] = empty ↔ (∀ n1. n0 ≤ n1 ∧ ¬ n0 + n < n1 → buf[n1] = empty) |
buf[n0 + n] = empty, n0 + n < # buf, isempty(buf, n0, n), ∀ n2. n0 ≤ n2 ∧ n2 < n0 + n → buf[n2] = empty ⊦ ∀ n1. n0 ≤ n1 ∧ ¬ n0 + n < n1 → buf[n1] = empty
n0 + n < # buf, isempty(buf, n0, n), ∀ n2. n0 ≤ n2 ∧ n2 < n0 + n → buf[n2] = empty, ∀ n1. n0 ≤ n1 ∧ ¬ n0 + n < n1 → buf[n1] = empty ⊦ buf[n0 + n] = empty