I don't know of very many projects that do "heavy math" in perl. usually high end math problems run in very long times, forcing peop,e to over optimize the application that is solving the problem. You tend to see many long running math apps as C with a lot of inline asm to optimize the time the program takes. For instance I don't think you could even come close to many of the C/ASM PI calculators out there in perl (even if you are using XS/inline C. I would think that there are many proof of algo consepts done in perl -- but most are converted to optimized C/asm for production runs.

-Waswas