Ask A Scientist Mathematics Archive

Question:  What's the hardest math problem you've ever done?
 mr john riddle

Answer 1:
     It's invariably the one that I'm working on currently.  This time
it's: What's the geometrical meaning of the central extension of the algebra
of diffeomorphisms of the circle?
 jlu

Answer 2:
I've been working on a problem in Number Theory off and on for almost
ten years called "the Collatz Conjecture" aka "the 3X + 1 problem".
Let f(x) be a function defined on the positive integers such that:
 
f(x) = x/2 if x is even
f(x) = (3*x+1)/2 if x is odd
 
Then the conjecture is: iterates of f(x) will eventually reach 1 for any
initial value of x. Various cash prizes have been offered for the proof
or disproof of this conjecture.
 hawley