Author Archives: John Eichelberger

It’s been a very long but very fun term. Cheers!

On this fine Halloween, we discussed what it means to act geometrically, vindicating our work on hyperbolicity with a discussion of the Schwarz Lemma. First, recall the definition from last week: Definition. A group G is hyperbolic if it acts geometrically … Continue reading →

Today’s lecture was held outside, in the lovely warmth and sunlight. We considered two ways to approach the following statement. Claim. If , then is free. A Geometric Group Theory Proof Instead of proving this claim directly, we started with … Continue reading →

Wednesday’s class was a review of groups, a “whirlwind-review” of the basics of graphs and trees, and a look at actions on symmetry groups of geometric object.  Groups, Reviewed To begin with, we reviewed group presentations, of form . For … Continue reading →