I have found nLab very helpful as well, for when I need to look up a definition of some higher-categorical construction and I don't have a book or paper on hand to refer to. I have thought many times, though, that it would be great if there were some Web-accessible database of categories which are commonly encountered in mathematics, and their properties; I often find that I need to know if certain kinds of limits, or colimits, or injective envelopes, etc. etc. etc. exist in a particular category, and having some central database to look at (which would hopefully tell me what I need to know as well as cite whatever paper the result was proved in) would be a lot quicker than having to either search the literature for such a result or try to re-prove the result myself. Does anyone know if there have been any attempts to compile such a database? Thanks, Andrew S. On Tue, 18 Aug 2009, Michael Shulman wrote:
I love the nLab too, but I'm not sure that "merging" is the right word; probably the two are serving slightly different purposes. The overall nLab is not really organized like a textbook or designed to be read linearly; writing a textbook requires additional thought. But there is certainly no reason why the two can't share material and link to each other as appropriate. And/or one could choose to write a textbook as a section of the nLab rather than on Wikibooks (if, for instance, one preferred its offerings in the way of mathematical typesetting).
Mike
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