** Next:** Theorem
** Up:** Guitton: Huber solver
** Previous:** Introduction

This part follows closely Kelley 's *Iterative Method for Optimization* Kelley (1999).
We start here with a series of definitions:
- 1.
- is positive definite if for all
- 2.
- is
*spd* if is positive definite and symmetric
- 3.
- () is a global minimizer if
for all

The Euclidian norm is also defined as
Now, I give sufficient conditions that a minimizer exists for a function *f*.

** Next:** Theorem
** Up:** Guitton: Huber solver
** Previous:** Introduction
Stanford Exploration Project

4/27/2000