GABLE was a prototype geometric algebra system. The prototype was successful, but we have moved on to C++ and Java libraries for geometric algebra. However, feel free to download the Matlab software and tutorial; if you encounter any problems or have any comments, please email them to us: L.Dorst@uva.nl and/or firstname.lastname@example.org. although be aware that we no longer support GABLE.
If you are serious about studying geometric algebra, you should look at the tutorials and other material we have created with our newer software, and you might considering looking at our book, which discusses geometric algebra in more depth.
To get the most from the tutorial, you should down-load the Matlab software: