Misc :

- Pathfinder networks (PFNET) and algorithms
- Take benefit of the idle time on your computer
- Bitcoin, a cryptographic currency

- The "impossible Puzzle" of Freudenthal
- X and Y are two different integers, greater than 1, with sum less than 100. Sassy and Patrick are two mathematicians; Sassy knows the sum X+Y, Patrick knows the product X*Y, and both know the information in these two sentences. The following conversation occurs.
- Patrick says "I cannot find these numbers."
- Sassy says "I was sure that you could not find them. I cannot find them either."
- Patrick says "Then, I found these numbers."
- Sassy says "If you could find them, then I also found them."
- What are these numbers?