Documentation

Complexitylib.Algebraic.LowerBound.Cutwidth.Extractor.Strong.Block.Recursion.Parameters

Finite bounds for a constant-rate block schedule #

Let T be the initial explicit condenser budget. If the initial width covers 4^h*Q entropy bits and 3*(24*T)+6*E ≤ 2*Q, the actual rate-three condensers satisfy both splitting inequalities at every executed level. Each width stays between its entropy threshold and the initial width; each seed has at most 24*T bits. The aggregate block payload is at most twice the initial width, and a positive leaf reserve bounds the number of blocks by the initial entropy threshold.

This conservative finite schedule is an arithmetic deduction for the condense-and-split program, whose splitting requirements come from Chattopadhyay--Goodman--Liao, Corollary 5.4 of Affine Extractors for Almost Logarithmic Entropy, https://eccc.weizmann.ac.il/report/2021/075/. The global reserve premise is explicit. A concrete reserve choice, asymptotic seed estimate, and encoded recursive evaluator are separate.

The final entropy threshold is the supplied leaf reserve.

Every executed level retains one quarter of the preceding entropy threshold.

theorem Algebraic.Cutwidth.Extractor.recursiveBlockWidth_bounds (initial h Q E : ℕ) (capacity : recursiveBlockEntropy h Q 0 ≤ initial) (budget : 3 * (24 * explicitCondenserBudget initial (recursiveBlockEntropy h Q 0) E) + 6 * E ≤ 2 * Q) {i : ℕ} (level : i ≤ h) :
recursiveBlockEntropy h Q i ≤ recursiveBlockWidth initial h Q E i ∧ recursiveBlockWidth initial h Q E i ≤ initial

Each actual block holds its scheduled entropy and fits within the initial width.

theorem Algebraic.Cutwidth.Extractor.recursiveBlock_split_budget (initial h Q E : ℕ) (capacity : recursiveBlockEntropy h Q 0 ≤ initial) (budget : 3 * (24 * explicitCondenserBudget initial (recursiveBlockEntropy h Q 0) E) + 6 * E ≤ 2 * Q) {i : ℕ} (level : i < h) :
recursiveBlockEntropy h Q (i + 1) ≤ recursiveBlockWidth initial h Q E (i + 1) ∧ recursiveBlockWidth initial h Q E (i + 1) + recursiveBlockEntropy h Q (i + 1) + E ≤ recursiveBlockEntropy h Q i

Every executed condenser output satisfies the two finite splitting inequalities.

theorem Algebraic.Cutwidth.Extractor.recursiveBlockSeedWidth_le (initial h Q E : ℕ) (capacity : recursiveBlockEntropy h Q 0 ≤ initial) (budget : 3 * (24 * explicitCondenserBudget initial (recursiveBlockEntropy h Q 0) E) + 6 * E ≤ 2 * Q) {i : ℕ} (level : i ≤ h) :

The initial logarithmic budget bounds each level's actual field seed width.

theorem Algebraic.Cutwidth.Extractor.recursiveBlock_payload_le (initial h Q E : ℕ) (capacity : recursiveBlockEntropy h Q 0 ≤ initial) (budget : 3 * (24 * explicitCondenserBudget initial (recursiveBlockEntropy h Q 0) E) + 6 * E ≤ 2 * Q) {i : ℕ} (level : i ≤ h) :
2 ^ i * recursiveBlockWidth initial h Q E i ≤ 2 * initial

All block payloads together occupy at most twice the initial width at every level.

theorem Algebraic.Cutwidth.Extractor.recursiveBlock_count_le (h Q : ℕ) {i : ℕ} (positive : 0 < Q) (level : i ≤ h) :

Positive leaf entropy bounds the number of blocks by the initial entropy threshold.