[Imprint][Data Privacy Statement][E-Mail]

View long theorem info. View the proof. Back to main index. View the specification. View theorem base summary, View theorem base listing, the used properties by spec, the dependency list, the symbol table,

Proof step 30 from proof shiftright-rec-8-neg (previous step)

8 < j, i < 0, 0 < j, ∀ i, j0. i→n(j0) < i→n(j) → 8 ≤ j0 ∧ i < 0 ∧ 0 < j0 ∧ 0 ≤ j0 → i >> j0 = (i - 255) / 256 >> (j0 - 8) ⊦ j = 8, j = 0, (i - 1) / 2 >> (j - 1) = (i - 255) / 256 >> (j - 8)

User applied rule apply induction

And obtained the following new goals

Proof step 31:
(i - 1) / 2 >> (j - 1) = ((i - 1) / 2 - 255) / 256 >> (j - 1 - 8), 8 < j, i < 0, 0 < j, ∀ i, j0. i→n(j0) < i→n(j) → 8 ≤ j0 ∧ i < 0 ∧ 0 < j0 ∧ 0 ≤ j0 → i >> j0 = (i - 255) / 256 >> (j0 - 8) ⊦ j = 8, j = 0, (i - 1) / 2 >> (j - 1) = (i - 255) / 256 >> (j - 8)

Rule argument

subst: [i, j0] → [(i - 1) / 2, j - 1]

Additional information

Used simplifier rules: rightshift-zero: ⊦ i >> 0 = i;% ⊦ i→n(i - 1) < i→n(i) ↔ 0 < i;% ⊦ i ≤ j - i0 ↔ i + i0 ≤ j;% ⊦ ¬ i ≤ j ↔ j < i;%0 < j ⊦ i / (* j) < 0 ↔ i + j ≤ 0;% ⊦ i + (j - i0) = i + j - i0;% ⊦ (* i) + i0 - (* j) = (i - j) + i0;% ⊦ i + j + i0 = (i + j) + i0;% ⊦ i + j = j + i;% ⊦ i + (* j) ≤ (* j0) ↔ i ≤ j0 - j;% ⊦ i ≤ ~1 ↔ i < 0;% ⊦ ¬ i < j ↔ j ≤ i;% ⊦ i < j → (¬ ¬ j ≤ i ↔ false);% ⊦ i < j - i0 ↔ i + i0 < j;% ⊦ 0 < i → (i ≤ 1 ↔ i = 1);% ⊦ 1 ≤ i ↔ 0 < i;% ⊦ i ≠ j → (i ≤ j ↔ i < j);% ⊦ i < j → ¬ j < i;%i + 1 = i0 ⊦ j < (* i0) → ¬ (* i) < j; Used terms: (i - 1) / 2, j - 1