<\body> as an interface> An important feature of is it's ability to communicate with extern systems. For computer algebra systems or other scientific computation systems, this is typically done in shell-like sessions, in which it is possible to evaluate commands and display the results in a nice, graphical way. Some systems can also be used more in the background as scripting languages. See for a list of existing plug-ins and more documentation on these systems. <\traverse> <\initial> <\collection>