Paul writes: I've heard the term "lluf subcategory" meaning "subcategory with the same objects but possibly fewer morphisms". Is there a reference for this usage? I think I have to plead guilty for this. But I don't know where the crime was first committed in print. 10-Jan-2002 10:02:19 -0400,1048;000000000000-00000000

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I've heard the term "lluf subcategory" meaning "subcategory with the same objects but possibly fewer morphisms". Is there a reference for this usage?

Two references to "lluf subcategories" that I am aware of:

1. Categories for Types - Roy L. Crole - 1993 - page 49

2. Practical Foundations of Mathematics - Paul Taylor - 1999 - page 211 (where the term "wide subcategory" is suggested as synonym).

And thank you, Paul, for bringing this up, since it reminded me to ask:

Does anyone know the origin of the term "lluf", or how it should be pronounced?

I've been looking through Peter Freyd's papers, and the earliest occurrence of "lluf" that I can find is in "Algebraically complete categories", published in the proceedings of the 1990 Como meeting (Springer LNM 1488, 1991). It is used there (on page 101) without comment or explanation, which suggests that Peter must have used it before, but I can't find an earlier occurrence. A lower bound for its first occurrence is provided by Peter's paper "Choice and well-ordering" (Ann. Pure Appl. Logic 35, 1987), where the concept occurs without being so named. As regards pronunciation, I've always thought that since it looks like a Welsh word it should be pronounced as such, i.e. (approximately) "thleeve". (The Welsh "ll" doesn't correspond to any sound representable by a combination of consonants in English.) Peter Johnstone 11-Jan-2002 08:51:08 -0400,743;000000000000-00000000

Charles found the phrase "wide subcategory" and it appears that way in CTCS. Much preferred IMHO. But chacun a son (de)gout. On Wed, 9 Jan 2002, Peter Freyd wrote:

Paul writes:

I've heard the term "lluf subcategory" meaning "subcategory with the same objects but possibly fewer morphisms". Is there a reference for this usage?

I think I have to plead guilty for this. But I don't know where the crime was first committed in print.

10-Jan-2002 22:41:20 -0400,4643;000000000000-00000000