Regrouping
One of the more beautiful sights in Cambridge is the long avenue of London plane trees on Jesus Green, a delight at every time of year, equally in summer sun or on a grey autumn day with the leaves falling. It so raises the spirits every time we walk out into town. And we’ve really needed that: it has been a stressful month with a serious health scare at home. Which has very happily turned out to be a false alarm (with thanks to the NHS for extremely rapid investigations and scans). But it has all been, shall we say, rather distracting …
We are regrouping. And I’m at last in the mood again for logical matters. In particular, I’m back to revising Introducing Category Theory. I still (over-optimistically?) hope to get a Version 1.2 out by the end of the year — more than just an update for corrections, but with fewer radical changes than could warrant it being appropriately called a second edition. In the last few days, I’ve been wrangling with the early chapters on groups and categories of groups once more, I hope to some reasonably good effect.
More generally as I go through the book, I find I’m doing scattered amounts of rephrasing and making minor alterations for clarity. But so far, I’ve found no real horrors crying out for correction; and at this point, the only major additions I want to make are (1) some brief remarks about the idea of monoidal categories since these are flavour of the month (I’ll be interested to see Noson Yanofsky’s brand new book) and (2) an expanded/improved treatment of structural set theory/ETCS (I’ve been spurred on to want to do better on that in part by recently re-reading this extremely helpful piece on set theories and type theories by Mike Shulman). I’ll post any interesting-enough new sections here.
I confess that, while de-stressing after recent events, I treated myself to some serious Apple Therapy, in the form of the new, very mini, Mac Mini to drive my Apple Studio Display. I’m delighted and can warmly recommend. An indulgence, yes (though it seemed absurdly cheap with an education discount). But it really is impressive.
The LaTeX file for the 450 page category theory book (with a lot of commutative diagrams in TikZ which notoriously slow things down) compiles to a PDF in 23.80 seconds on my M2 MacBook Air, and 14.40 seconds on the M4 Mini. That’s a very noticeable speed bump. I’ll now have to work out how to to use the memoize package which avoids having to recompile stable diagrams every time you update the PDF which should speed things even more.
You don’t want my views about the way the world out there is going to hell in a handcart (for where does one start?). So I’ll try to keep posts here — or at least the non-logical ones! — more heartening. For today, then, here is a musical treat to pass on. A few years back, the BBC relayed a live concert by the wonderful Elisabeth Brauß in Birmingham playing Schubert’s Four Impromptus D.899. They have recently rebroadcast her extraordinarily sensitive performance, and for two or three weeks you can find it again here on BBC Sounds (starting at 1.48 in). Real balm for the troubled soul.
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