Understanding the Significance of the Yoneda Lemma in Category Theory
The Yoneda Lemma is often regarded as a cornerstone of category theory, but what makes it so important? This discussion explores its foundational role and the reasons behind its prominence, despite its straightforward proof.

Sheafification of G
31.6K views • Jul 18, 2025

About this video
I'm sure we've all heard of the Yoneda Lemma before, but why does it get so much hype in category theory when the result itself is quite elementary to prove?
Well, you're not going to get a good answer from me.
__________
Errata (as usual):
1:22 - The composition is backwards... thanks @danshap36!
__________
Timestamps:
00:00 - Introduction
00:45 - What is the Yoneda Lemma?
01:55 - Elementary tl;dw
04:52 - Is this loss(y)?
08:19 - Natural transformations
10:41 - Elements of a presheaf
12:49 - Thx 4 watching
Well, you're not going to get a good answer from me.
__________
Errata (as usual):
1:22 - The composition is backwards... thanks @danshap36!
__________
Timestamps:
00:00 - Introduction
00:45 - What is the Yoneda Lemma?
01:55 - Elementary tl;dw
04:52 - Is this loss(y)?
08:19 - Natural transformations
10:41 - Elements of a presheaf
12:49 - Thx 4 watching
Video Information
Views
31.6K
Likes
1.9K
Duration
13:32
Published
Jul 18, 2025
User Reviews
4.6
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