As an outsider, let me say something about outsiders in this. In a word, "Where's the rosetta stone?" Here's what I mean. I'm a numerical analyst/computer scientist. I'm ancient (much older than 50), so I was brought up in the Dark Ages pre-computer, set- theoretic world. So I pick up Walters book, "Categories and computer science" and read it. At the end, I say: OK, how do I work this into my undergraduate classes? graduate classes? They've had discrete math in the Math department and got no introduction to category theory. What does it tell students about designing their current homework program? What does this mechanism tell an undergrad about writing data structures? What does it tell them about performance in networks? I see the point about denotational semantics etc; I know none of our grad students could read Walters. But if you can't retrain undergrads to switch from what they know to a new world, it is not accepted because as grad students they're not going to accept it either. Now you can take a purist view and go your own way and I can go mine. That's kinda silly. Hence, I'd settle for a rosetta stone. Who will help me write an undergraduate text book on classic computability concepts but from a categorical point of view? Pick your favorite text. I suspect it would not be any help to anyone's tenure case because it's all so obvious --- except to outsiders --- but it would be a interesting and perhaps useful pedagogical device. Would such a text be thinner or thicker than the original? What new insights would we receive? best regards, steve -------- D. E. Stevenson, Department of Computer Science Director, Institute for Modeling and Simulation Applications Clemson University, Clemson, SC 29634-0974 864.656.5880 http://www.cs.clemson.edu/~steve On Apr 4, 2006, at 5:49 PM, Ronnie Brown wrote:

I have not been able to keep up with all this correspondence, but would like to take up Vaughan Pratt's counter to Reinhard Boerger's point saying: `it can't be done' which would be better as a question: `How should one do it?'

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