Boundary Dehn twists are excellent!

Ty Ghaswala, CEMC, University of Waterloo

Imagine you are handed a compact orientable surface with one boundary component. It is known that the Dehn twist about a curve isotopic to the boundary component is not quite like all the other Dehn twists. For one thing, it is central in the mapping class group of the surface. It turns out that such Dehn twists have a special property called co-finality in every left ordering of the mapping class group, making them even more amazing than originally thought! I will tell you what all of this means, and time permitting, we will discuss the implications for mapping class group actions on the real line.

This is joint with Adam Clay.

MC 5417