### Who are Various?

#### Posted by David Corfield

If you’re in the Manchester area on Saturday 4 October with not much to do, why not join me at MIMS Workshop on New Directions in Philosophy of Mathematics? I’m talking there, and will be discussing what I’ve been writing for a contribution to a book on Lautman.

While looking at what can be seen of Lawvere’s *Categories of Space and of Quantity* article mentioned here, I remembered that Saunders Mac Lane had written the preceding article in the book – *The Protean Character of Mathematics*. In view of the fact that one of the cases Lautman treats is Galoisian duality, I was delighted to find on turning back the page in Google books that on page 13 he writes

Janelidze, 1988 Categorical formulation of Galois Structure

Various, 1990 One adjunction handles Galois and much more

Unfortunately, pages 11-12 are missing, but if memory serves, these two entries are just the end of a list starting out with Galois.

By ‘Janelidze, 1988’, is Mac Lane referring to

Galois theory in categories: the new example of differential fields, Proc. Conf. Categorical Topology in Prague 1988, World Scientific 1989, 369-380?

And who are ‘Various, 1990’, what is their single adjunction, and what is ‘much more’?

Posted at September 10, 2008 9:12 AM UTC
## Re: Who are Various?

Presumably, Janelidze’s abstract categorical Galois theorem is on Mac Lane’s mind.