12 Mar 2014

Hanging out with group theory

Submitted by Anne Bentley, Lewis & Clark College

Six group theory enthusiasts met in cyberspace in February to share our passion for the subject and compare notes about our approaches to teaching it.  The courses taught by attendees ranged, predictably, from sophomore level to graduate.  Advice and examples flew in all directions.  Favorite textbooks included Carter (, Harris & Bertolucci (needs a review, not recommended for MO theory), and Hargittai & Hargittai (recommended for beautiful images of symmetrical objects).  Did you know that some textbooks define the positive rotation direction as counter-clockwise, while others define it as clockwise?  Be sure to align yourself consistently with your textbook in this matter.

The conversation generated a flurry of ideas for future learning objects. Five slides about conventions in group theory, Tanabe Sugano diagrams and example problems, a description of how to skip the projection operator without anyone taking offense: all of these are in preparation.  In the meantime, check out Joanne’s collection of LO's on group theory (

At the risk of sending readers away from VIPEr’s website, we shared some favorite sites that we have used in our courses.  Dean Johnston’s symmetry animations are essential to the beginning learner (  An excellent TED talk about symmetry Is available (, as is a talk about crystals with five-fold symmetry (






That TED talk by Marcus du Sautoy is a perfect introduction for symmetry! Definitely using it in my class.