Dan Piker

Ahlfors circle maps and total reality: from Riemann to Rohlin This is a prejudiced survey on the Ahlfors (extremal) function and the weaker {\it circle maps} (Garabedian-Schiffer's translation of "Kreisabbildung"), i.e. those (branched) maps effecting the confor...

There's also an extended edition arxiv.org/abs/1211.3680

I guess the crow took a scenic route

The talk was part of this series illustratingmath.org/node/42 and the recording will appear later on www.youtube.com/@Illustratin...

I enjoyed a presentation from Jason Cantarella yesterday, during which he showed a nice cyclic deformation of the Borromean rings. @henryseg.bsky.social made a comment about whether a similar motion would be possible as a Möbius transformation, which inspired me to create this:

For anyone else curious what each one represents:

This surface can be described as a diagonal on the hypersphere. See thread here for some explanation:
mathstodon.xyz/@Danpiker/11...

Diagonal on a 3-sphere - 3D model by dpiker Diagonal on a 3-sphere - 3D model by dpiker

skfb.ly/puHHF

Hopfodrome - 3D model by dpiker Hopfodrome - 3D model by dpiker

skfb.ly/puwQw

Please help my mug did a topology

Danpiker (@Danpiker@mathstodon.xyz) Attached: 1 image

oof, that compression is grim. Same file on Mastodon for comparison mathstodon.xyz/@Danpiker/11...

A triply orthogonal system of surfaces from stereographic projection of Hopf coordinates

If you select the image icon, it lets you upload in gif format, and the preview shows it animated, but when you post it's just a still. If you select the filmstrip icon you can upload as gif, and it plays when posted (though still as a compressed video not actually gif)

Here's the same uploaded as mp4 at 30fps

nope, still stutters in the app. Plays smoothly on mobile browser though.

Trying at 30fps

Testing out the new gif upload option here.
It appears they still actually get converted to mp4, but with different compression to if you upload as mp4 (twitter was similar). This was uploaded as a 50fps gif. It loops smoothly when viewed on desktop, but stutters on the android app :(