I saw a comment box at the end of that thread, and I succeeded in posting a test comment on that thread just now, so I’m not sure what the problem is.

]]>.

Yeah, I see that there were replies a week ago, but right now it’s impossible to post anything.

]]>And then there’s a link to questions, and there are ones that wasn’t mentioned in lecture. E.g. 3-rd says “What do mathematicians usually call the thing that Fong and Spivak call a poset?”, and you even said in lecture that you answered that question. But… you didn’t, if you enter word “math” in browser search, you won’t find an occurrence in the first lecture.

And in general, I’m surprised that lectures are soo tiny, did people succeed learning Category Theory from them?

]]>Here are the lectures:

• Lecture 55 – Chapter 4: Enriched Profunctors and Collaborative Design

• Lecture 56 – Chapter 4: Feasibility Relations

• Lecture 57 – Chapter 4: Feasibility Relations

• Lecture 58 – Chapter 4: Composing Feasibility Relations

• Lecture 59 – Chapter 4: Cost-Enriched Profunctors

• Lecture 60 – Chapter 4: Closed Monoidal Preorders

• Lecture 61 – Chapter 4: Closed Monoidal Preorders

• Lecture 62 – Chapter 4: Constructing Enriched Categories

• Lecture 63 – Chapter 4: Composing Enriched Profunctors

• Lecture 64 – Chapter 4: The Category of Enriched Profunctors

• Lecture 65 – Chapter 4: Collaborative Design

• Lecture 66 – Chapter 4: Collaborative Design

• Lecture 67 – Chapter 4: Feedback in Collaborative Design

• Lecture 68 – Chapter 4: Feedback in Collaborative Design

• Lecture 69 – Chapter 4: Feedback in Collaborative Design

• Lecture 70 – Chapter 4: Tensoring Enriched Profunctors

• Lecture 71 – Chapter 4: Caps and Cups for Enriched Profunctors

• Lecture 72 – Chapter 4: Monoidal Categories

• Lecture 73 – Chapter 4: String Diagrams and Strictification

• Lecture 74 – Chapter 4: Compact Closed Categories

• Lecture 75 – Chapter 4: The Grand Synthesis

• Lecture 76 – Chapter 4: The Grand Synthesis

• Lecture 77 – Chapter 4: The End? No, the Beginning!

To some extent this is just an excuse to (finally) introduce *categories, functors, natural transformations, adjoint functors* and *Kan extensions*. Great stuff, and databases are a great source of easy examples.

Here are the lectures:

• Lecture 34 – Chapter 3: Categories

• Lecture 35 – Chapter 3: Categories versus Preorders

• Lecture 36 – Chapter 3: Categories from Graphs

• Lecture 37 – Chapter 3: Presentations of Categories

• Lecture 38 – Chapter 3: Functors

• Lecture 39 – Chapter 3: Databases

• Lecture 40 – Chapter 3: Relations

• Lecture 41 – Chapter 3: Composing Functors

• Lecture 42 – Chapter 3: Transforming Databases

• Lecture 43 – Chapter 3: Natural Transformations

• Lecture 44 – Chapter 3: Categories, Functors and Natural Transformations

• Lecture 45 – Chapter 3: Composing Natural Transformations

• Lecture 46 – Chapter 3: Isomorphisms

• Lecture 47 – Chapter 3: Adjoint Functors

• Lecture 48 – Chapter 3: Adjoint Functors

• Lecture 49 – Chapter 3: Kan Extensions

• Lecture 50 – Chapter 3: Kan Extensions

• Lecture 51 – Chapter 3: Right Kan Extensions

• Lecture 52 – Chapter 3: The Hom-Functor

• Lecture 53 – Chapter 3: Free and Forgetful Functors

• Lecture 54 – Chapter 3: Tying Up Loose Ends