# Tannakian Reconstruction

Published articles for Tannakian Reconstruction.

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## Tannakian reconstruction

DevFeed: [Tannakian reconstruction](<https://devfeed.tech/articles/tannakian-reconstruction-28863.md>)

Original publisher: [Read original article](<https://bartoszmilewski.com/2026/07/14/tannakian-reconstruction/>)

Author: Bartosz Milewski

Published: 2026-07-14T10:51:53Z

Content type: tutorial

Language: en

Sources: [Bartosz Milewski's Programming Cafe](<https://devfeed.tech/sources/bartosz-milewski-s-programming-cafe.md>)

Topics: [structure](<https://devfeed.tech/topics/structure.md>)

Tags: [category-theory](<https://devfeed.tech/tags/category-theory.md>), [fiber-functor](<https://devfeed.tech/tags/fiber-functor.md>), [tannakian-reconstruction](<https://devfeed.tech/tags/tannakian-reconstruction.md>)

### AI overview

An explanatory article introduces Tannakian reconstruction through an analogy of superimposed photographs, then describes how functors, fiber functors, natural transformations, and ends can recover source-category morphisms.

### Source excerpt

Two friends, Alice and Bob, live in the same city, but on the opposite sides of a wide river. Every night, Bob looks at the lights on the other side and tries to guess, which one belongs to Alice. They come up with a clever arrangement: Alice will turn on her lights for 10 minutes [...]

## Tambara Equipment

DevFeed: [Tambara Equipment](<https://devfeed.tech/articles/tambara-equipment-28862.md>)

Original publisher: [Read original article](<https://bartoszmilewski.com/2026/07/11/tambara-equipment/>)

Author: Bartosz Milewski

Published: 2026-07-11T08:13:34Z

Content type: article

Language: en

Sources: [Bartosz Milewski's Programming Cafe](<https://devfeed.tech/sources/bartosz-milewski-s-programming-cafe.md>)

Topics: [modules](<https://devfeed.tech/topics/modules.md>), [Haskell](<https://devfeed.tech/topics/haskell.md>), [Code](<https://devfeed.tech/topics/code.md>)

Tags: [category-theory](<https://devfeed.tech/tags/category-theory.md>), [code](<https://devfeed.tech/tags/code.md>), [double-categories](<https://devfeed.tech/tags/double-categories.md>), [double-category](<https://devfeed.tech/tags/double-category.md>), [haskell](<https://devfeed.tech/tags/haskell.md>), [modules](<https://devfeed.tech/tags/modules.md>), [optics](<https://devfeed.tech/tags/optics.md>), [proarrow-equipment](<https://devfeed.tech/tags/proarrow-equipment.md>), [profunctors](<https://devfeed.tech/tags/profunctors.md>), [structure](<https://devfeed.tech/tags/structure.md>), [tambara-modules](<https://devfeed.tech/tags/tambara-modules.md>), [tannakian-reconstruction](<https://devfeed.tech/tags/tannakian-reconstruction.md>), [theory](<https://devfeed.tech/tags/theory.md>), [transformation](<https://devfeed.tech/tags/transformation.md>)

### AI overview

This article explains Tambara modules through category theory and illustrates the concepts with Haskell code. It discusses their relationship to profunctors, monoidal actions, double categories, proarrow equipment, and Tannakian reconstruction.

### Source excerpt

I was originally attracted to category theory when trying to understand Haskell optics. I was puzzled by the van Laarhoven's functor representations and Kmett's use of Tambara modules. By playing Tetris with the Yoneda lemma I was able to make some progress, attacking more and more esoteric topics. With a group of researcher and students [...]