Demetrix is a Java-based process modelling system. The goal of the project is to develop a flexible framework for managing complex process models using Petri-Net-oriented methodologies (state-task networks and resource-task networks).
GeoGebra is free and multi-platform dynamic mathematics software for learning and teaching geometry, algebra, statistics, and calculus. Download the free software at http://www.geogebra.org. Find the source code at http://www.geogebra.org/trac
Mathematical modelling and computer simulating of military operations.
Free, open source application that parses math expressions and simplifies it, if possible.