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@MartinEscardo@mathstodon.xyz

Post #2636089

2026-05-05 21:33 UTC

@JacquesC2@types.pl If you are formalizing e.g. category theory, where everything is already done and organized in textbooks, then it is much easier to adopt the encyclopedic approach. If you are investigating a new subject, e.g. injective types, you don't know in advance what the better definitions are, what theorems will end up with some parts of their proofs reused somewhere else, and what you are going to discover in this journey. So there is a big difference. Doing new mathematics is trial-and-error and exploration. Formalizing mathematics that somebody else has already organized, post-fact, in textbooks is an entirely different matter, because somebody else did the organization for us. You can only organize something **after** it has been done. Things don't grow in an organized way. It is hopeless, as mathematical practice shows, to try to do this in advance. In the process of doing new mathematics, you always discover, the next day, that something you did yesterday can be generalized, simplified, and refactored. And this goes on day after day. This is what a blackboard looks like. A collection of better and better ideas. An encyclopedia, on the other hand, is the result of this journey + a big reorganization effort. @egbertrijke@mathstodon.xyz @gallais@mamot.fr

Replies (1)

  • @JacquesC2@types.pl 2026-05-06 00:34

    @MartinEscardo@mathstodon.xyz Your main point remains: doing new mathematics with a theorem prover as blackboard is different. I've done that too, I love it, and fully agree that it is both pleasurable and very different than writing either a library or an encyclopedic reconstruction. However, allow me to be pedantic for a moment: pretty much everyone who has formalized category theory, in particular, comes to hate how it is organized in textbooks. I know agda-categories is seriously sub-optimal because it follows the classical organization way too much. Other formalizations are better for having thrown off those shackles! There are similarly lots of papers, indeed from the mathlib people, who report the same: the classical textbooks were not the best source. And, of course, same is true for MathComp in Rocq. @egbertrijke@mathstodon.xyz @gallais@mamot.fr

    Open ##2636090