Igor wrote:

> Also, it seems to be a mistake not to provide more time for Chapter 3, or make a pause for at least a few weeks after it (the concept is called spaced learning). This is the cornerstone chapter - either you understand it, and everything collapses at once, or there is no reason to actually proceed.

Actually the first half of Chapter 4 - the half I've covered so far - uses almost nothing from Chapter 3. It picks up where Chapter 2 left off: it continues the study of preorders, and \\(\mathcal{V}\\)-enriched categories where \\(\mathcal{V}\\) is a preorder. So don't let any difficulties with Chapter 3 stop you from starting Chapter 4.

But yes, Chapter 3 touches on a huge amount of material: it's the first place one meets full-fledged _category theory_ instead of preorder theory! I could easily have spent twice as much time on it. The main reason I didn't is that I knew it would condemn me to not finishing the course by the time I have to start teaching (not for fun - for pay!) in late September.

I was relieved that Chapter 4 returned to preorder theory, which is much easier to explain since one never needs to discuss equations between morphisms.

However, the second half of Chapter 4 is about monoidal categories, so here one needs to understand full-fledged categories again. And I would like to cover monoidal categories.

The amount of time it would take to fully explain the chapters keeps increasing after that.

> My advice is not to give up John, but in order not to burn yourself down, postpone new lectures until the October/November.

I'm going to be busy teaching actual classes from the end of September until April... including an advanced course on category theory, but also undergraduate courses like calculus, and graduate courses like real analysis. I'll have three students finishing their PhD theses next spring, so I'll need to spend a lot of time reading and editing their theses. And then I have three other grad students, and I'm working part-time for Pyrofex and Metron. So, the first time I could manage to continue this course would be April 2019... and frankly, I'm getting tired just thinking about it!