Lambda the Ultimate

Categories for Everybody
started 3/3/2004; 1:43:23 PM - last post 3/15/2004; 1:09:15 PM

Andrei Formiga - Categories for Everybody

3/3/2004; 1:43:23 PM (reads: 260, responses: 6)

I searched it, but apparently no one has mentioned this before. It's a book developed from lecture notes for a course at Carnegie Mellon University, by Steve Awodey. The focus of the book seems obvious, judging by its title, but I can't give any criticism here. Maybe someone more knowledgeable in the matter can look at it and give an opinion.

Categories for Everybody

andrew cooke - Re: Categories for Everybody

3/3/2004; 2:21:24 PM (reads: 270, responses: 0)

thanks for that. i like the presentation - it seems to be fairly relaxed - although it's still a bit rough in places (some figures missing, strange low-res text (generated from postscript?), and he blithely assumes the reader knows what a scott domain is on page 9, which goes against the "everybody" in the title).

Andris Birkmanis - Re: Categories for Everybody

3/5/2004; 4:15:42 AM (reads: 195, responses: 1)

My criticism would be a low attention to the concept of a diagram, diagrams "just appear" without much preface.

Ehud Lamm - Re: Categories for Everybody

3/5/2004; 4:23:15 AM (reads: 202, responses: 0)

diagrams "just appear" without much preface.

For a minute there I thought you were writing about UML

DocOlczyk - Re: Categories for Everybody

3/9/2004; 11:47:47 AM (reads: 146, responses: 1)

Something I'm very7 much confused about, when constructing an arrow category ( alternatively a morphism category ), what gaurantees the existence of (h,k) as defined in

http://planetmath.org/encyclopedia/ExampleOfCategory.html

( if you can't get the page, (h,k) is the morphism ).

Marc Hamann - Re: Categories for Everybody

3/9/2004; 12:06:39 PM (reads: 159, responses: 0)

what gaurantees the existence of (h,k)

The definition. ;-)

If h or k doesn't exist in C then (h,k) doesn't exist in D. If h and k do exist in C, then by the definition of D (h,k) is a morphism between f and g in D.

DocOlczyk - Re: Categories for Everybody

3/15/2004; 1:09:15 PM (reads: 98, responses: 0)

<it>diagrams "just appear" without much preface.</it>

That's generally the way ot happens in mathematics. The only place where I've even seen formal definitions of diagrams is in "Categories for CS" papers.