Bartosz Milewski Extends Yoneda Lemma to Double Categories

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Programmer and mathematician Bartosz Milewski published a new blog post on September 13, 2026, exploring the Yoneda Lemma in the context of double categories. The piece extends a foundational concept from category theory into the more complex framework of double categories. Milewski's blog is known for making advanced mathematical and functional programming topics accessible to a technical audience. The post appeared on Hacker News with minimal engagement, receiving only 3 points and no comments at the time of aggregation.

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