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It won't be very long because I am a very young researcher but here's what I am working on.
Who wrote Generic Figures and Their Glueings?
Marie and Gonzalo Reyes and Houman Zolfaghari ... the book itself is available online (just use Google).
One thing I like a lot about that book is that it works many concrete examples of topos-theoretic constructions, in the setting of presheaf categories where you can really calculate things. The running examples include sets, graphs, reflexive graphs, and discrete dynamic systems (or "evolutive sets," as the authors call them).
Its a really nice book but I wish they had discussed that is the free cocompletion of . I feel like that fact is what justifies the 'generic figures' perspective.
Update for the end of my internship.
So you'll be in Lyon, right?
Yes, working with Matteo Mio.
Update after a great first month of PhD.
That's impressive! How do you manage to do that much?
I don't think I am being very productive on all fronts. I like to have many different projects so that whenever I lose focus on one, I can try to think about the others. Only 4 and 5 have real timing requirements so I can work on the first three at my own pace.
Update after a great first semester of PhD.
Ralph Sarkis said:
Update after a great first semester of PhD.
- I have just submitted a paper on quantitative algebraic reasoning with Matteo Mio and Valeria Vignudelli. I am bit exhausted from the obligatory pre-submission rush, so I'll discuss this with you a bit later.
- Project 2 and 3 from last time are stalled, but I'll try to revive them soon.
- I am crossing my fingers for the ACT adjoint school, Fillipo Bonchi's project is in the perfect direction towards my dream thesis.
- My category theory course last semester was great. I didn't end up teaching too much because I let younger students teach, but I enjoyed helping them prepare lectures, and we still covered the contents (up to Yoneda) of my book. I had very good feedback on the book, and also lots of ideas of new things to add.
- I am a TA for a semantics class this semester. Not as cool as teaching a full course, but still very enjoyable.
Hi Ralph, your work seems intriguing to me. I wonder whether you took into consideration Rosicky's work on metric monads and what would be the link between the two.
I have read this paper and this other related paper, but I am not comfortable with enriched categories, locally presentable categories and accessible categories, so I don't understand every detail. From my understanding, the solution we crafted to talk about operations which are not nonexpansive (see Second extension axis in the introduction) is not something either paper can deal with. That was my main motivation for writing this paper, every thing I read on (categorical) universal algebras deals with operations of type or , where the product or function space is constructed categorically, i.e.: with the categorical product or its adjoint.
Now, our solution is to almost take a product (we take a lifting of the product) as the domain of the operation. It turns out, as our paper shows, this still leads to a nice theory (very close to Mardare et al.'s approach).
In order to really understand the link between our paper and Rosicky's, I would like to extend our solution to lift the function space too (i.e. have more general arities as in Ford et al.'s paper), and translate our work to the categorical language used in Rosicky's paper (the Lawvere-Linton way of doing universal algebra). I don't see how to do this right now, but I am looking for solutions, and I wanted to ask here at some point for some help.
Ralph Sarkis said:
I have read this paper and this other related paper, but I am not comfortable with enriched categories, locally presentable categories and accessible categories, so I don't understand every detail. From my understanding, the solution we crafted to talk about operations which are not nonexpansive (see Second extension axis in the introduction) is not something either paper can deal with. That was my main motivation for writing this paper, every thing I read on (categorical) universal algebras deals with operations of type or , where the product or function space is constructed categorically, i.e.: with the categorical product or its adjoint.
Now, our solution is to almost take a product (we take a lifting of the product) as the domain of the operation. It turns out, as our paper shows, this still leads to a nice theory (very close to Mardare et al.'s approach).
In order to really understand the link between our paper and Rosicky's, I would like to extend our solution to lift the function space too (i.e. have more general arities as in Ford et al.'s paper), and translate our work to the categorical language used in Rosicky's paper (the Lawvere-Linton way of doing universal algebra). I don't see how to do this right now, but I am looking for solutions, and I wanted to ask here at some point for some help.
Thanks Ralph. I also told Jiri about your work, I think that's a quite cool development.
That's awesome to hear!
Quick update.
Great! Let us know how it goes with that high school student. Good luck on your trip to Montreal. Prakash is a great guy. If nothing goes wrong I'll see you at ACT2022 in Glasgow.
great! I'm glad you're trying it out - yes, let us know how it goes, and I'm available if you want to discuss any ideas.
I am getting back to you (especially @Christian Williams and @John Baez) on my internship.
I spent 4 days with a high school student (16 years old) trying to show him what research in maths/cs is. Out of those 4 days, around 1.5 days was spent on discovering the 2-dimensional syntax for relations described in Christian's talk. Every time I introduced a new piece of syntax, we spent a lot of time finding examples and asking simple questions before moving on, and by the end of the week, we were able to cover relations, composition of relations, implications, vertical and horizontal composition of implications. I am not sure what to think of the end result. On the one hand, he and I had fun exploring these ideas and I believe the graphical syntax definitely helped him throughout our work. On the other hand, on the last day, he was supposed to prepare a quick explanation of what he did during the week to share with other students who did a similar internship, but he told me he was not confident enough in his understanding of relations, so we switched to a more concrete subject.
Let me give a bit more details. It was really hard for him to find examples and questions by himself. I think the main problem is that he is not used to abstract reasoning, and I think I was bad at pointing out the relevant patterns. For instance, whenever we dealt with composition of two relations, he had to draw the points in the colors and links between them before understanding (that's I think the main good point about the syntax: the points and links picture for a relation embeds well in the syntax). This was easier when dealing with relations between a set and itself, in particular, familial relationships (dad, cousin, grandparent, etc.) between humans and the usual orders on integers. I found he was not very enthusiastic about our findings, so I'd like to look for better examples of things to prove (for me, the best thing we have proved is that if a relation is reflexive, then it is dense, we had lots of examples of dense and non-dense relations and we figured out all dense ones were reflexive, so we showed the implication (very easily) graphically).
TLDR: Teaching relations to a high school student is very hard, but I believe it is less hard when using a graphical syntax.
Thanks for the report! Teaching is always hard, and it's harder when you're teaching something new... but it sounds like you both had fun and discovered interesting things.
Thanks Ralph, this is interesting. Could you share some implications and composites that the student made?
also, above it looks like you posted a screenshot of a video you made, but I'm having trouble finding the link.
We made lots of compositions with familial relations:
We had person allergic to ingredient and ingredient inside recipe implies person shouldn't try this recipe.
When I tried doing more abstract things we looked at the empty, identity and full relation on a set, and we saw how they compose with each other and with an arbitrary relation.
Christian Williams said:
also, above it looks like you posted a screenshot of a video you made, but I'm having trouble finding the link.
This is not a video (the progress bar is from the screenshot I made of the Rick and Morty scene), it is the thumbnail for a (in person) talk I am giving next week.
Okay, nice. Did you compose implications, in sequence and/or in parallel?
Not that much, that was the last thing we did and I don't remember the examples we came up with.
Update.
Update.
Update for the start of term.
What do you mean by quantitative reasoning? Does it have anything to do with graded linear logic?
Very briefly, instead of deriving equalities between terms we want to derive distances between terms. It has some interesting subtleties like the fact that the context (variables) may contain quantitative information as well, so the distance between terms depends on the distance between inputs.
In the process of reading your paper and it seems very exciting so far.I'm interested in more specific things related to combining fuzziness and logic/algebra/"Theory B".For example,i'm interested in a structure similar to a generic category with product of homsets equipped with some partial fuzzy relation (a metric or mutual information of ouput for example) so instead of strict morphism equality we have a metric that we can optimize.I'm also interested in theretically analyzing (and then using those results in practice) the case of adding a unary fuzzy relation (idk what to call it,too many terms.a statistic?a real-valued function?) to homsets inspired by The Category Theoretic arithmetic of information where generalized axioms are derived from information theory for a function I:Hom(C)->R so that it would be a 'measure of information' and then some really interesting examples are given.I wonder if there would be any interesting relationship between the unary I operator and the binary 'distance' of morphisms if for example both are some information theretic functions,like the connection between kolmogorov and statistical complexity. Basically i'm intrested in quantitative generalized algebraic theories with a special case being categories,mostly the use case being using those structures as a way of knowledge representation and an architectural principle for AI.If there's any papers like that I would love to hear about them.
Also,it feels validating that this whole combination of fuzziness and Theory B stuff is coming back into vogue when I was thinking about it for years :)
I haven't thought too much about the multisorted case yet. I am guessing if if you want all the morphisms to form a metric space, it will not be too hard to adapt our results, but making every hom-set a metric space on its own will be more difficult with something like algebraic theories (the hom-sets are dependent types).
Your description made me think of normed or weighted categories which I learned about here.
I believe we are probably rediscovering some things known to the fuzzy logic community, but also probably providing new insights. I witnessed an inspiring discussion about this at a talk given by Radu Mardare on this paper.
Generalized algebraic theories are basically dependent types as far as i understand and im interested in exploring fuzzifying commutativity and see what would happen to universal constructions in that case.i have a few intuitions specific to (co)limits but in general i think a strict definition of a universal construction could be seen as a target of optimization for a fuzzy predicate of commutativity. the limit of zero entropy (perfect commutativity/match) would coincide with equality.thanks for the references!
Update (to motivate myself).
I like that you feel the need to write a book on category theory rather than doing only research :sweat_smile:
Very cool that you want to link every basic notion to the definition in your book. Looks like a quite futuristic way to present math. I mean it's like on the wikis, but implementing at the level of research is very nice because it's supposed to make the material accesible to anyone with enough motivation
Thanks for the validating kind words Jean-Baptiste :smiling_face_with_hearts:
Ralph I mentioned this recently on another thread but I have recently discovered and started using a LaTeX package called "Semantic Tex" or sTeX which I use to add nice markup to mathematical documents (hyperlinks between definitions)
It facilitates breaking up a long document like a book into many small pieces which can be assembled together, in a more sophisticated way than just using \input or \include, in the sense that cross-references still work right between different files.
You can also reuse pieces more easily (a long definition you want to include somewhere else with the same notation)
And it exports to html in a fairly readable way, they have a simple webserver app that they supply with the semantic tex package that basically turns your paper or book into an interlinked wiki with things split up / arranged the same way you arrange your tex files.
It's not perfect, it's a research project under continuing evolution. There are new features being added regularly and they don't always work right. But the core features of the library that have been there for a whlie work.
Update (before the start of term).
Update.
I love it when people include a lot of examples and explanations at the start of their thesis. I think introductory chapters like that can be a great stand-alone resource, while also facilitating easier understanding of the main results. What you have already looks useful and interesting to me, so I've saved a copy for my future reference! :smile:
🙏🏼 I did try to write both chapters independent of each other and of the thesis, and the 10% missing is mostly about making that even more true. I am also planning to have a chapter devoted to examples/applications of our work, but that will inevitably require reading (at least skimming) the main chapter.
Update.
Update.
The paper that you link in 4. looks so cool! I remember that Nathan Haydon made a talk about the calculus of relations of Peirce (from 1897!) at FMCS 2022 which was more like a philosophy talk (he talked about the history of this calculus in the work of Peirce if I remember correctly) and Paweł Sobociński seemed not very convinced about this stuff because the talk wasn't like an usual math talk. This is so cool that they ended writing a paper together (and with the two other authors) improving this mysterious calculus of Peirce into a graphical language for first-order logic! By the way for the anecdote the slides of Nathan from summer 2022 are here.
Well, they had already written a paper together in 2020 so it seems my psychological skills are not very good :sweat_smile:. Anyway, I love this paper.
In fact it looks like Pawel is the supervisor of Nathan. Perhaps that why he was talking to him in a critical way :sweat_smile: Sorry, now I stop poluting your thread.
Filippo Bonchi is scheduled to talk about this for Topos tomorrow.
Thanks! I was scared I could not attend the talk because I'll be travelling from Ottawa to my parents near Bayonne in France tomorrow, but it looks like the talk will start just one hour after I'll arrive at their home. I hope they will not be angry at me if I go away some time to listen to the talk :)
:joy: I think it will be available on YouTube after it is livestreamed.
Yes, that's the other option :joy:
Update.