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Proof step 27 from proof rightshift-8-01 (previous step)

i→n(j) < 2, i < ~128, ~256 < i, ~256 ≤ i, i < 0, ∀ i, j0. i→n(j0) < i→n(j) → i→n(j0) < # int2bytes(i) → i >> 8 * abs(j0) = bytes2int(firstn(# int2bytes(i) - i→n(j0), int2bytes(i))) ⊦ (i / 256 - 1) >> 8 * (abs(j) - 1) = bytes2int(firstn(2 - i→n(j), i2b(~1) ' + i2b(i) ')), j = 0, i % 256 = 0

User applied rule insert rewrite lemma

And obtained the following new goals

Proof step 28:
⊦ n ≠ 1 → (n < 2 ↔ n = 0)
Proof step 29:
¬ i→n(j) ≠ 1, i→n(j) < 2, i < ~128, ~256 < i, ~256 ≤ i, i < 0, ∀ i, j0. i→n(j0) < i→n(j) → i→n(j0) < # int2bytes(i) → i >> 8 * abs(j0) = bytes2int(firstn(# int2bytes(i) - i→n(j0), int2bytes(i))) ⊦ (i / 256 - 1) >> 8 * (abs(j) - 1) = bytes2int(firstn(2 - i→n(j), i2b(~1) ' + i2b(i) ')), j = 0, i % 256 = 0

Rule argument

seq: ⊦ n ≠ 1 → (n < 2 ↔ n = 0) subst: [n] → [i→n(j)] rotate: F spec: nat-basic1 inst: name: lstwo

Additional information

Used simplifier rules: ⊦ i→n(i) = 0 ↔ i = 0; Used terms: i→n(j)