Take any tetrahedron, and for each face compute its perimeter P, and the solid angle Ω it subtends as seen from the opposite vertex.
Daniil Rudenko and @robinhouston have found a linear relationship between 1/P and cot(Ω/2).
https://mathoverflow.net/questions/336464/a-curious-relation-between-angles-and-lengths-of-edges-of-a-tetrahedron/336777 …pic.twitter.com/6a8q1uzCrX
-
Show this thread
-
The slope of each line is: 12 times the volume of the tetrahedron, divided by the product of its four face perimeters! The intercept is a bit more complicated. I give a formula for it at the linked Math Overflow page, but maybe it can be expressed in simpler geometric terms.
4 replies 0 retweets 9 likesShow this thread -
Replying to @gregeganSF @robinhouston
That’s amazing.. it makes me wonder if it’s a 3D generalization of the famous V-E+F=2 relation ..
2 replies 0 retweets 0 likes -
2 replies 0 retweets 1 like
-
Replying to @lisyarus @InertialObservr and
TL;DR: the alternating sum of numbers of k-dim 'cells' (points - edges + faces - solid 3D cells + ...) is a topological invariant χ.
2 replies 0 retweets 1 like -
Nikita, I’m glad that I’m nocturnal and therefore our time zones have a nontrivial overlap
2 replies 0 retweets 1 like
also my girlfriend is Russian and I had her translate one of your tweets yesterday.. idk why I’m mentioning that but I am
-
-
Wow! Which one?
1 reply 0 retweets 0 likes -
I don’t know how to respond to that in a way that will not get me in trouble
0 replies 0 retweets 1 like
End of conversation
New conversation -
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.