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# Category Archives: Category theory

## A Gentle Introduction

You can now download here the first instalment (88pp.) of a Gentle Introduction to category theory, reworked from my Notes on Category Theory. Gentleness is relative, of course. Peter Johnstone plans, in his first 13 lectures for this (academic) year’s Part … Continue reading

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## Notes on Basic Category Theory, v.9

I have tinkered a little with the previous version of the Notes, removing some fairly obvious typos, adding some remarks or improving a proof here and there, also adding a proof or two. That’s perhaps three or four pages of new material in all. … Continue reading

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## Notes on Basic Category Theory, v.8a/8b

It’s a balancing act. On the one hand, I don’t want to annoy readers with over-frequent announcements of minor revisions. On the other hand, I don’t want to keep propagating flawed versions when I have an improved offering in hand! … Continue reading

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## Notes on Category Theory, v.8

At long last — more or less exactly nine months since I started intermittently writing them — there is a first complete version of my Notes on Category theory (as they are now called). Or at least, the Notes are complete in … Continue reading

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## Notes on Category Theory, v.7

Progress seems to have been a bit slow for various reasons, but I have now added two short-ish chapters to the Notes on Category Theory. One is a chapter on Exponentials added between the chapters on limits and the start of … Continue reading

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## Notes on Category Theory v.6b

Illness (not so great) followed by fortnight’s holiday (really excellent) stopped work on category theory for a while. Very slowly getting back to it. But in the meantime, a number of people have very kindly been sending corrections to the … Continue reading

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## Notes on Category Theory v.6a

A number of people have very kindly sent corrections to the last version of Notes on Category Theory. There were some possibly confusing typos and also a downright wrong proof. Embarrassing. So here’s a “maintenance upgrade”, making some needed repairs. [Added: a … Continue reading

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## Notes on Category Theory v.6

Here is an updated version of my on-going Notes on Category Theory, now over 150 pp. long. I have added three new chapters, at last getting round to the high point of any introduction to category theory, i.e. the discussion of adjunctions. … Continue reading

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## Notes on Category Theory v.5

Here is an updated version of my on-going Notes on Category Theory, now 130 pp. long. I have done an amount of revision/clarification of earlier chapters, and added two new chapters — inserting a new Ch. 7 on categories of categories and issues … Continue reading

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## Category theory again

The category theory page here has been much expanded with links to (i) some online lecture notes, and (ii) some books which are freely (and legitimately!) available online in one form or another. I am not at all aiming to … Continue reading

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