I'm trying to understand how certain fractal structures behave -- e.g., medieval Gothic churches as approximations to fractals, or aerogel-type structures, etc. Typical finite element analysis of bulk structures is 'dense', in that it produces dense matrices. Fractal structures, on the other hand, produce extremely sparse matrices that are barely connected. Is there any branch of matrix analysis that deals with such 'supersparse' matrices (I'll call them that until I find that someone else has already given them a better name) ?? I'm also trying to find out if there are any existing codes for analyzing such structures; I'd be willing to bet that existing codes aimed at dense structures would perform poorly relative to a code that is optimized for fractal structures. Obviously, finite matrix theory can only model truly fractal structures down to some finite level, but perhaps some scheme for recursive block matrices might be the right way to deal with these things.