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IV · Queueing theory

Little's law

What it is

L = λW. Average number in system = arrival rate × average time in system.

Where it lives

Sizing thread pools, queue depth, request-in-flight tuning, every capacity-planning spreadsheet.

The key insight

Holds for any stable queue, regardless of arrival or service distribution. The most-used theorem in operations.

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Across the foundations
V Speed of light Physics & hardware limits V Memory hierarchy Physics & hardware limits V Landauer principle Physics & hardware limits V Amdahl's law Physics & hardware limits VI One-way functions Cryptographic foundations VI Discrete log Cryptographic foundations VI Birthday attack Cryptographic foundations VI AEAD Cryptographic foundations
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