:pari
<a href="http://pari.math.u-bordeaux1.fr/AUTHORS">the PARI group</a>
http://pari.math.u-bordeaux1.fr/
PARI/GP est un système de calcul formel très répandu, conçu pour des calculs rapides en arithmétique (factorisations, théorie algébrique des nombres, courbes elliptiques...) mais contient aussi un grand nombre de fonctions pour le calcul matriciel, sur les développements limités, les nombres algébriques, etc. ainsi que de nombreuses fonctions transcendantes. 
:maxima

http://maxima.sourceforge.net/
Maxima is a system for the manipulation of symbolic and numerical expressions, including differentiation, integration, Taylor series, Laplace transforms, ordinary differential equations, systems of linear equations, polynomials, and sets, lists, vectors, matrices, and tensors. Maxima yields high precision numeric results by using exact fractions, arbitrary precision integers, and variable precision floating point numbers. 
:graphviz
<a href="http://www.graphviz.org/Credits.php">Credits</a>
http://www.graphviz.org/
Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks. Automatic graph drawing has many important applications in software engineering, database and web design, networking, and in visual interfaces for many other domains. 
can be used through the slibs <span class="tt">graph/graphviz</span>, <span class="tt">draw/graphviz</span> and <span class="tt">draw/graphvizpoints</span>

:gap
<a href="http://www.gap-system.org/Contacts/People/people.html">The GAP Group</a>
http://www.gap-system.org/
GAP is a system for computational discrete algebra, with particular emphasis on Computational Group Theory. GAP provides a  programming language, a library of thousands of functions implementing algebraic algorithms written in the GAP language as well as large data libraries  of algebraic objects. See also the overview  and the description of the  mathematical capabilities. GAP is used in research and teaching for studying groups and their representations, rings, vector spaces, algebras, combinatorial structures, and more. 
:float_calc,integer_calc

http://www.gnu.org/software/bc/
interface to bc ; bc -l

:yacas
<a href="http://yacas.sourceforge.net/credits.html">Credits</a>
http://yacas.sourceforge.net/homepage.html
YACAS is an easy to use, general purpose Computer Algebra System, a program for symbolic manipulation of mathematical expressions. It uses its own programming language designed for symbolic as well as arbitrary-precision numerical computations. The system has a library of scripts that implement many of the symbolic algebra operations; new algorithms can be easily added to the library. YACAS comes with extensive documentation (hundreds of pages) covering the scripting language, the functionality that is already implemented in the system, and the algorithms we used. 

:jmol


:geogebra
