I've come across a rather interesting CS problem during work that I thought I'd throw out there. The problem is this: given a finite lattice (L, ⊑) (our problem has a lattice that is also distributive, so you may presume that) and a node x in that lattice, efficiently compute the set S ⊆ L = { y ∈ L : x ⊏ y ∧ ∄ z x ⊏ z ⊏ y }. This is well defined ( Read more... )

From Talk is talk, kill is kill: Knuth, 4.5.2, theorem D: If u and v are integers chosen at random, the probability that gcd(u,v)=1 is 6/pi^2
So if you give someone an infinite amount of random integers, they can use those to calculate pi by checking how many of those are prime to one another.
Yet another demonstration of the unreasonable ( Read more... )