Java PHASER Project 

Phaser is an intuitive program for graphically and numerically analyzing dynamical systems on a computer. Such systems include multi-dimensional Difference Equations, Iterated Function Systems, and Ordinary Differential Equations exhibiting bifurcation, periodic, equilibria, chaotic, and strange attraction behaviors. Phaser captures and manifests these dynamical phenomena with its powerful Views.

Ed Connell's Elements of Abstract & Linear Algebra

This is a foundational textbook on abstract algebra with emphasis on linear algebra. You may download parts of the book or the entire textbook for free.