Andrew Salch wrote: 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?
I don't know of any such attempts. I've always wanted such a database! An obvious place to create it is on the nLab. I just started one: http://ncatlab.org/nlab/show/database+of+categories but it will only become interesting after a while. If everyone here contributes an entry or two today, it will be interesting by tomorrow! Best, jb [For admin and other information see: http://www.mta.ca/~cat-dist/ ]