# Blog Archive

Yoneda Lemma
August 1, 2021
Bridging the gap between formal and informal presentations of the Yoneda Lemma.

The Hask Category
June 1, 2021
A quick reference for understanding the

**Hask**category of Haskell functions between data types.
Abstract Algebra: Modules
May 13, 2020
Vector spaces over a field are a special case of the more general notion of modules over a ring. Rather than the long list of axioms normally presented in textbooks, we see how an algebraic view of vector spaces helps to motivate the definition of modules.

Expectation Maximization
November 26, 2015

**Expectation Maximization**is an iterative algorithm used for maximum likelihood estimation on latent variable models. Following (Neal & Hinton 1998), we present expectation-maximization as coordinate ascent on the**Evidence Lower Bound**. This perspective takes much of the mystery out of the algorithm and allows us to easily derive variants like**Hard EM**and**Variational Inference**.