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Proof step 9 from proof bytes2int-size-07 (previous step)

0 ≤ b2i(by), 0 ≤ 256 * bytes2int(i2b(~1) ' + by ' + bytes.butlast) + band(255, b2i(bytes.last)) + 2 ^ (8 * (n→i(# bytes) + 1) - 1), ∀ by, bytes0. # bytes0 < # bytes → 0 ≤ b2i(by) ∧ 0 ≤ bytes2int(i2b(~1) ' + by ' + bytes0) + 2 ^ (8 * (n→i(# bytes0) + 1) - 1) → false ⊦ bytes = []

User applied rule insert elim lemma

And obtained the following new goals

Proof step 10:
bytes = bytes1 + by0 ', 0 ≤ b2i(by), 0 ≤ 256 * bytes2int(i2b(~1) ' + by ' + bytes1) + band(255, b2i(by0)) + 2 ^ (8 * (n→i(# bytes) + 1) - 1), ∀ by, bytes0. # bytes0 < # bytes → 0 ≤ b2i(by) ∧ 0 ≤ bytes2int(i2b(~1) ' + by ' + bytes0) + 2 ^ (8 * (n→i(# bytes0) + 1) - 1) → false ⊦ bytes = []

Rule argument

seq: bytes ≠ [] ⊦ by = bytes.last ∧ bytes0 = bytes.butlast ↔ bytes = bytes0 + by ' subst: [bytes, by, bytes0] → [bytes, by0, bytes1] rotate: T spec: list-last inst: bytelist name: last-elim

Additional information

Used simplifier rules: bytes ≠ [] ⊦ by = bytes.last ∧ bytes0 = bytes.butlast ↔ bytes = bytes0 + by '; (elim) Used terms: bytes, by0, bytes1