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Proof step 7 from proof bytes2int-zero-03 (previous step)

bytes2int(bytes.butlast) * 256 + band(b2i(bytes.last), 255) = 0, by ∈ bytes, ∀ by, bytes0. # bytes0 < # bytes → bytes2int(bytes0) = 0 ∧ by ∈ bytes0 → by = i2b(0) ⊦ by = i2b(0), # bytes = 1, bytes = []

User applied rule insert elim lemma

And obtained the following new goals

Proof step 8:
bytes = bytes1 + by0 ', bytes2int(bytes1) * 256 + band(b2i(by0), 255) = 0, by ∈ bytes, ∀ by, bytes0. # bytes0 < # bytes → bytes2int(bytes0) = 0 ∧ by ∈ bytes0 → by = i2b(0) ⊦ by = i2b(0), # bytes = 1, 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