Author Archives: Danny Calegari

kleinian, a tool for visualizing Kleinian groups

It’s been a while since I last blogged; the reason, of course, is that I felt that I couldn’t post anything new before completing my series of posts on Kähler groups; but I wasn’t quite ready to write my last … Continue reading

Posted in Groups, Hyperbolic geometry, Visualization | Tagged , | 3 Comments

Kähler manifolds and groups, part 2

In this post I hope to start talking in a bit more depth about the global geometry of compact Kähler manifolds and their covers. Basic references for much of this post are the book Fundamental groups of compact Kähler manifolds by … Continue reading

Posted in Algebraic Geometry, Complex analysis, Geometric structures, Groups | Tagged , , , , , , , , | Leave a comment

Kähler manifolds and groups, part 1

One of the nice things about living in Hyde Park is the proximity to the University of Chicago. Consequently, over the summer I came in to the department from time to time to work in my office, where I have … Continue reading

Posted in Algebraic Geometry, Complex analysis, Geometric structures, Lie groups | Tagged , , , , | 8 Comments

Liouville illiouminated

A couple of weeks ago, my student Yan Mary He presented a nice proof of Liouville’s theorem to me during our weekly meeting. The proof was the one from Benedetti-Petronio’s Lectures on Hyperbolic Geometry, which in my book gets lots … Continue reading

Posted in Complex analysis, Euclidean Geometry, Rigidity | Tagged , , , | 7 Comments

Scharlemann on Schoenflies

Yesterday and today Marty Scharlemann gave two talks on the Schoenflies Conjecture, one of the great open problems in low dimensional topology. These talks were very clear and inspiring, and I thought it would be useful to summarize what Marty … Continue reading

Posted in 3-manifolds, 4-manifolds | Tagged , , , , , | 9 Comments

You can solve the cube – with commutators!

After a couple years of living out of suitcases, we recently sold our house in Pasadena, and bought a new one in Hyde Park. All our junk was shipped to us, and the boxes we didn’t feel like unpacking are … Continue reading

Posted in Groups | Tagged , , | 15 Comments

Chiral subsurface projection, asymmetric metrics and quasimorphisms

Last week I was at Oberwolfach for a meeting on geometric group theory. My friend and collaborator Koji Fujiwara gave a very nice talk about constructing actions of groups on quasi-trees (i.e. spaces quasi-isometric to trees). The construction is inspired … Continue reading

Posted in Groups, Hyperbolic geometry, Surfaces | Tagged , , , , , , , , | 4 Comments