Math.NET is an opensource initiative to build and maintain toolkits covering fundamental mathematics, targetting advanced but also every day needs of .Net developers.
Math.NET Numerics aims to provide methods and algorithms for numerical computations in science, engineering and every day use. Covered topics include special functions, linear algebra, probability models, random numbers, interpolation, integral transforms and more.
Math.NET Filtering (previously Neodym) aims to provide a toolkit for digital signal processing, offering an infrastructure for digital filter design, applying those filters to data streams using data converters, as well as digital signal generators.
Math.NET Symbolics is a basic opensource computer algebra library for .Net, Silverlight and Mono, written entirely in F#.
Math.NET Spatial aims to become a geometry library for .Net, Silverlight and Mono.