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John Baez (Sep 20 2023 at 09:19):The first Edinburgh Category Theory seminar of the year takes place in less than two hours! But it should meet roughly weekly:
Physical coordinates: 12:00, Wed 20 Sep, room 5.46, Bayes Centre, Edinburgh
Virtual coordinates:
https://ed-ac-uk.zoom.us/j/83513503673
Meeting ID: 835 1350 3673
Passcode: Hodge2023
There's a new website for the seminar (thanks, Adrian!):
https://www.maths.ed.ac.uk/~adona/seminar.html
First of all, we'll make a plan for who's going to speak during the rest of the semester.
John Baez (Sep 20 2023 at 09:20):Then Tom Leinster will give a rather informal talk on some work in progress:
A categorical view of the Banach fixed point theorem
This is a speculative talk inspired by recent work of Arij Benkhadra and Isar Stubbe. On the one hand, the Banach fixed point theorem is a staple of undergraduate courses on metric spaces. On the other, metric spaces can usefully be seen as enriched categories. This raises the question of whether the Banach fixed point theorem can be understood categorically. I will talk about the search for an answer, opening up avenues of investigation without, yet, being able to say what lies at the end of them.
Nathanael Arkor (Sep 20 2023 at 19:32):Will any of the talks be recorded? I'd ne interested in watching them.
John Baez (Sep 20 2023 at 20:20):I don't think they're being recorded.
Cole Comfort (Sep 20 2023 at 23:25):John Baez said:
The first Edinburgh Category Theory seminar of the year takes place in less than two hours! But it should meet roughly weekly:
Physical coordinates: 12:00, Wed 20 Sep, room 5.46, Bayes Centre, Edinburgh
Virtual coordinates:
https://ed-ac-uk.zoom.us/j/83513503673
Meeting ID: 835 1350 3673
Passcode: Hodge2023There's a new website for the seminar (thanks, Adrian!):
https://www.maths.ed.ac.uk/~adona/seminar.htmlFirst of all, we'll make a plan for who's going to speak during the rest of the semester.
Please keep us updated! I will be in Scotland soon during my post-PhD homelessness and I need things to do!
John Baez (Sep 21 2023 at 08:31):Okay, I don't promise to keep announcing talks here - you can get those at the website. But I'm giving the next talk, not next week but the week after that: Wednesday. October 4th. Here's my talk:
The representation theory of the symmetric groups is clarified by thinking of all representations of all these groups as objects of a single category: the category of Schur functors. These play a universal role in representation theory, since Schur functors act on the category of representations of any group. We can understand this as an example of categorification. A "rig" is a "ring without negatives", and the free rig on one generator is , the rig of polynomials with natural number coefficients. Categorifying the concept of commutative rig we obtain the concept of "symmetric 2-rig", and it turns out that the category of Schur functors is the free symmetric 2-rig on one generator. Thus, in a certain sense, Schur functors are the next step after polynomials.
John Baez (Sep 21 2023 at 08:33):Next, Clark Barwick will speak on Wednesday October 11th.
John Baez (Oct 02 2023 at 10:48):If anyone wants to read the lecture notes for my Wednesday October 4th talk at the Edinburgh Category Theory Seminar, they can do it here:
John Baez (Oct 02 2023 at 10:48):And, just to repeat: this seminar is not being recorded, but you can attend via Zoom following the instructions above.
John Baez (Oct 02 2023 at 10:55):Information about the seminar will show up here. Right now we know something about who will be speaking when, but nothing about what they'll say (except for my talk on October 4th):
11 Oct Clark Barwick
18 Oct Matthew Di Meglio
25 Oct Alexey Elagin
1 Nov Adrián Doña Mateo
8 Nov Nesta van der Schaaf
15 Nov ?
22 Nov ?
29 Nov ?