Reservoir Sampling (Draft)

6 m

In this post, we study reservoir sampling, a technique for randomly choosing a sample from a large list. In practical scenarios, the list is often so large t...

Perfect Secrecy, or Not?

Cryptography is the science of designing systems that can withstand malicious attempts to abuse them. Every cryptographic scenario can be illustrated by the ...


Generalizations of the real and complex number systems

Group Actions

An introduction to the theory of group actions, covering examples, various counting principles, and Sylow’s theorems.

How to Read Commutative Diagrams

An introduction to commutative diagrams, a compact language for describing algebraic objects and structure-preserving maps between them.

Naïve Set Theory

A quick overview of elementary set theory, covering the basic terminology, relations and functions, equivalence relations and quotient sets, cartesian produc...

Killing the Hydra

20 m

On Kirby–Paris Hydra game, which involves killing off a particularly vicious modern variant of the Lernaean Hydra