Fisher's identity is useful to use in maximum-likelihood parameter estimation problems. In this post, I give its proof. The main reference is Douc, Moulines, Stoffer; Nonlinear time series theory, methods and applications.

## 2014/06/12

## 2014/06/04

### Batch MLE for the GARCH(1,1) model

## Introduction

In this post, we derive the batch MLE procedure for the GARCH model in a more principled way than the last GARCH post. The derivation presented here is simple and concise.

## 2014/01/30

### Convergence of gradient descent algorithms

## Introduction

In this post, I review the convergence proofs of gradient algorithms. Our main reference is: Leon Bottou, Online learning and stochastic approximations. I rewrite the proofs described in Bottou's paper but with more details about the points which are subtle to me. I tried to write the proofs as clear as possible so as to make them accessible to everyone.