[boost] Submit a library that compute the roots of a polynomial upto the 4th order

Hi, This is my first time that I wan to submit a library to boost. On http://www.boost.org/development/submissions.html, it mentioned boost vault, without explaining what it is. Can somebody let me know what it is? What is the difference between boost vault and boost sandbox? Do I need to submit my library to vault or sandbox? Where shall I put it? Thanks, Peng