6 citations · 12 across the 12 of their papers we have counts for
Showing math.DSShow all
3 papers · 1 filter
math.DS2008
The Euler class of planar groups
Danny Calegari
This is an exposition of the homological classification of actions of surface groups on the plane, in every degree of smoothness.
math.DS2006
Denominator bounds in Thompson-like groups and flows
Danny Calegari
Let T denote Thompson's group of piecewise 2-adic linear homeomorphisms of the circle. Ghys and Sergiescu showed that the rotation number of every element of T is rational, but the…
math.DS2005
Distortion in transformation groups
Danny Calegari, Michael H Freedman
We exhibit rigid rotations of spheres as distortion elements in groups of diffeomorphisms, thereby answering a question of J Franks and M Handel. We also show that every homeomorph…