Dear GeoGebraCAS friends, I have played a bit with the basics behind the CAS to build my own syntax. The basic idea is that the new GeoGebraCAS syntax is translated to Yacas syntax, evaluated by Yacas, and then translated back to GeoGebra syntax. of the CAS. The user does not notice all this, of course. You can play with the current CAS version at http://www.geogebra.org/webstart/alpha/geogebra-cas.jnlp Please have a look at my documentation of current features at http://ggbdev.pbwiki.com/Short-list-of-commands-for-the-prototype and add your thoughts and comments concerning the syntax and basic features right on that page. I also have put some questions for the Austrian group about some mentioned features. I will try to add buttons for "substitute", "expand", "factor", etc. soon (we have most of the functionality, I just need to fix some GUI bugs) and improve the user interface look and feel. Thanks, Markus -- Markus Hohenwarter, PhD Florida Center for Research in Science, Technology, Engineering, and Mathematics Florida State University, www.fcrstem.org GeoGebra: www.geogebra.org IGI: www.geogebra.org/IGI