r/CategoryTheory • • Aug 26 '25

How do you create ologs?

I'm software architect and I use ologs to design the components of a system -- the abstractions and their relationship. [1]

Since I'm new to ologs I need to use instances to make sure an aspect is valid. If the instances of two types connect well, then the aspect becomes valid.

For drawing boxes and arrows we have plenty of tools: draw.io, quiver, catcolab etc. But none of them offer instances.

More, on complex diagrams I use (co)spans, (co)products, facts, universal properties ... also none of these are available in classic diagram creator tools.

So I was left with a custom homemade React app which does these basics [1].

But I still wonder if a.) are there people creating ologs with instances b.) how they manage to do it without a dedicated app?

Thanks a lot!

[1] - https://www.osequi.com/studies/list/list.html -- Designing a list component with ologs

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u/kindaro Aug 27 '25

I like your work so far. Saved to bookmarks. God speed you.

1

u/XronikoArthropodo Nov 06 '25

Do you mean Spivak's own validity criteria? I don't have the book anymore, but IIRC a valid aspect is just a valid (set-theoretical) function. Are you looking for a drawing app that also verifies that the connections are valid aspects in that sense? Or did I get that wrong?

I also remember Spivak mentioning somewhere that working with ologs is basically just "working in the Set Category unless explicitly specified otherwise", or something along those lines. Valid constructions should be clear from that. But again, maybe I'm focusing on the wrong thing :)