# Useful Linear Algebra

*Posted: November 19, 2020*

Summary

A growing list of useful concepts and tools from linear algebra.

### Notation

- I use lowercase to represent scalars and vectors.
- I use uppercase to represent scalars and matrices.
- Unless otherwise stated, let be and complex.
- Unless otherwise stated, let be and complex.
- is the -th largest singular value of .
- is the -th largest eigenvalue of .
- is the column vectorization of .

### Vector Norms

### Matrix Norms

### Trace

(Cyclic Property) For properly sized matrices,