For some reason, I found myself minded to spend a bit of time tidying up the pages on posets and Galois connections that I was working on some weeks ago. They have the form of the first two chapters of something longer, something that may or may not get written — but these pages should have some stand-alone interest. Here’s the new version. As always, comments gratefully received. (Thanks so far to Tim Button and Luca Incurvati — and in particular to Nathan Bowler who gave a talk in which he explained the basic idea of syntax/semantics as a Galois connection, which inspired me to write these pages.)
[Later: Monday 30th June] And that link is now to a better version, with some paragraphs about quantifiers as adjunctions, and some superfluous material removed for later use.