| ∀ buf. 0 = datasize(buf, n) ↔ (∀ n0. n0 < n → buf[n0] = empty), ∀ n0. ¬ n < n0 → buf[n0] = empty ⊦ 0 = (buf[n] = empty ⊃ datasize(buf, n);n + 1) |
buf[n] = empty, ∀ n0. ¬ n < n0 → buf[n0] = empty, ∀ buf. 0 = datasize(buf, n) ↔ (∀ n0. n0 < n → buf[n0] = empty) ⊦ 0 = datasize(buf, n)
∀ n0. ¬ n < n0 → buf[n0] = empty, ∀ buf. 0 = datasize(buf, n) ↔ (∀ n0. n0 < n → buf[n0] = empty) ⊦ 0 = n + 1, buf[n] = empty