Linq Algebra aims to provide fundamental computer algebra algorithms on top of native Linq expressions. Write and manipulate your symbolic expressions in straight C# code.
Math.NET Linq Algebra is part of the Math.NET project. Available for free under the LGPL License.
If you have Github for Windows installed you can click here to fetch the sources, otherwise clone it in the shell with:
$ git clone git://github.com/mathnet/mathnet-linqalgebra.git
We use the Fork & Pull model, as common for Github projects. Instead of asking for permission, simply fork the project on Github, commit your changes in a separate branch and send a pull request to one of the maintainers. A maintainer will then merge your changes back to mainline, or work together with you on the changes if they are not acceptable yet. Only maintainers can write to mainline, but anyone can contribute - don't ask, do!
Tip: Once you've created a new branch in your fork you can already send a pull request for discussing your ideas, before actually committing anything to it.
Of course other contributions are very welcome as well, being it some publicity, more interesting code samples, code reviews, extending the documentation or even just some ideas. We're also looking for maintainers.