| subarray(buf, n0, n +1) = mkempbuf(n +1), n0 + n +1 ≤ # buf, ∀ buf, n0. subarray(buf, n0, n) = mkempbuf(n) ∧ n0 + n ≤ # buf → datasize(buf, n0 + n) = datasize(buf, n0) ⊦ datasize(buf, n0 + n +1) = datasize(buf, n0) |
⊦ datasize(buf, n + 1) = (buf[n] = empty ⊃ datasize(buf, n);n + 1)
subarray(buf, n0, n + 1) = mkempbuf(n + 1), n0 + n < # buf, ∀ buf, n0. subarray(buf, n0, n) = mkempbuf(n) ∧ n0 + n ≤ # buf → datasize(buf, n0 + n) = datasize(buf, n0) ⊦ (buf[n0 + n] = empty ⊃ datasize(buf, n0 + n);(n0 + n) + 1) = datasize(buf, n0)
Used simplifier rules: datasize-rec: ⊦ datasize(buf, n + 1) = (buf[n] = empty ⊃ datasize(buf, n);n + 1);% ⊦ m < n → n ≠ 0; (s)%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic% ⊦ m + 1 ≤ n ↔ m < n; (s)%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ m +1 = m + 1; (s)