Dear All, Happy New Year! Here are four new papers. 1. A general theory of self-similarity Improved, updated, merged version of a pair of papers I wrote some years ago. Just published in Adv. Math. http://arxiv.org/abs/1010.4474 2. The magnitude of metric spaces A numerical invariant of enriched categories, its application to metric spaces, and its apparently intimate relationship with geometric measure. http://arxiv.org/abs/1012.5857 3. Integral geometry for the taxicab metric Not category theory, but used in paper 2. http://arxiv.org/abs/1012.5881 4. An informal introduction to topos theory For people who know even less topos theory than me. http://arxiv.org/abs/1012.5647 Best wishes, Tom [For admin and other information see: http://www.mta.ca/~cat-dist/ ]