Lectures 1 & 2 of my minicourse on Coverages and Grothendieck Toposes are up on youtube. I’ll be giving the last talk this Friday.
youtu.be/G6kCMcRfRlI?...
12.05.2025 14:27
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Lectures 1 & 2 of my minicourse on Coverages and Grothendieck Toposes are up on youtube. I’ll be giving the last talk this Friday.
youtu.be/G6kCMcRfRlI?...
Ill be giving a minicourse for the next three weeks at the Topology, Geometry and Physics seminar tomorrow at 9am EST on my notes “Coverages and Grothendieck Toposes” (arxiv.org/abs/2503.20664), see www.zeinalian.com/workshop for more info!
Some new notes of mine are finally up!
Modern science wouldn’t exist without the online research repository known as arXiv. Three decades in, its creator still can’t let it go.
Woohoo! Nice job GC!
Woahh 🫣
What sorts of categorified connections do you not know how to find explicit descriptions of? By explicit/analytic here can I think “cocycle description”?
Ooo whats this from?
There are way too many categories of graphs, this is ridiculous. Most of them aren’t even toposes 😒
mathoverflow.net/questions/32...
#mathsky
Kurzgesagt calendars 2024 and 2025
Out with the old, in with the new.
#kurzgesagt #happynewyear
Congrats!! 🎊
Thank you! I taught precalculus and discrete math.
Thank you!
My first semester as a professor is over! Now I get to celebrate by nursing a sinus infection 😩.
I am so sorry to hear this, your papers and work are first class, best of luck!
🧐
Ricola
No clue. How I’d pronounce it: products.blains.com/600/106/1067...
This looks super cool! Would you be willing to give this (or a similar talk) at the NYC category theory seminar (in person or on zoom) next semester?
In this talk we will discuss concrete examples from topological spaces and graphs before moving to smooth manifolds and the recollement that gives rise to differential cohomology theories.
For more info: www.sci.brooklyn.cuny.edu/~noson/Semin...
Every recollement comes with a fracture square, which in some circumstances can be extended to a hexagon-shaped diagram of fiber sequences.
· Title: Recollements: gluing and fracture for categories.
· Abstract: Recollements provide a way of gluing two categories together along a left-exact functor, or conversely of obtaining a semi-orthogonal decomposition of a category by two full subcategories.
🧮 My good friend Matt Cushman @astragalus.bsky.social is giving a talk at the NYC category theory seminar this week, finishing up the seminar for this semester.
The deets:
· Speaker: Matthew Cushman, CUNY.
· Date and Time: Wednesday December 11, 2024, 7:00 - 8:30 PM. IN PERSON TALK
TFAE-theorems
Noticing this kind of thing is what I love about mathematicians
Loving this interview
www.simonsfoundation.org/2013/02/14/l...
On video 21 he discusses category theory!
A special case of this theorem is the classical result of Hilbert about elementary symmetric polynomials generating the algebra of all symmetric polynomials. I will also discuss how the logical complexity of a positive formula controls the size of the small substructures one must count.
The main result is that any isomorphism-invariant property of a finite structure can be checked by computing the number of isomorphic copies of small substructures it contains.
Abstract: I will discuss one part of my PhD thesis, in which I provide a categorification of the notion of a mathematical structure originally given by Bourbaki in their set theory textbook.
NYC Category Theory Seminar
Deets: www.sci.brooklyn.cuny.edu/~noson/Semin...
Speaker: Charlotte Aten, University of Colorado, Boulder.
Date and Time: Wednesday December 4, 2024, 7:00 - 8:30 PM. ZOOM TALK
Title: Invariants of structures.
Me: ah which one of my 100 projects should I work on today.
Narrator: he started another project that day.