# Unsolved Problem

1. Jun 29, 2009

### Dragonfall

Can somebody give me a little-known unsolved problem that can be stated without differential equations?

2. Jun 29, 2009

### Civilized

There are a variety of unsolved problems in graph theory which may be susceptible to elementary methods. A quick google search turned up this page:

http://math.fau.edu/locke/Unsolved.htm

3. Jun 30, 2009

### AUMathTutor

Does P = NP.

How many angels can dance on the head of a pin.

How much wood would a woodchuck chuck if a woodchuck could chuck wood.

How many grammatically correct English sentences are there containing at most n commas.

Etc.

4. Jun 30, 2009

### Civilized

AUMathTutor, most of those unsolved problems are well-known (the OP asked for ones which are little known), and furthermore I believe that the last three are ill-posed (since english has no formal grammar and angels and woodchucks are afaik undefined).

5. Jun 30, 2009

### HallsofIvy

Woodchucks will be surprized to learn that!
(You may know them better as groundhogs.)

6. Jun 30, 2009

### CRGreathouse

Halls, do you have an axiomatization of woodchucks handy?

7. Jun 30, 2009

### AUMathTutor

Actually, the P=NP problem is quite poorly known, if you look at how many people in the world have ever heard of it and divide by the number of people in the world.

Far more poorly known if you look at how many people understand what the question is actually asking.

Perhaps "well known" is a poorly-defined term.

8. Jun 30, 2009

### AUMathTutor

And I think the English sentence one is actually not so ill-posed. You might have to make certain stipulations, but you do that all the time in any mathematical problem.

9. Jun 30, 2009

### molinaro

I first heard the answer to that question over 30 years ago:

A woodchuck would chuck as much wood as a woodchuck could chuck if a woodchuck could chuck wood.

10. Jun 30, 2009

### Aten

Well...

- Does an odd perfect number(s) exist?
- Prove the abc conjecture.
- Explain the role of modulus in Parrondo paradox.
- What is the probability that an infinitely small object would become finitely big?(well "big bang" theory :)...no comment..
- Prove the Riemann hypothesis.

I can give you many more - but those are OK for now :). The problem about the probability is more than obvious(0 probability for such thing to happen regardless of the fairytales about "singularity"!...) - it's interesting how it objects the big bang funny hypothesis of singularity. I believe in the bang - just don't believe in the idiotic religious assumptions about creation. Religion and dogmatic science(why not every science?? should be forbidden by law...including present day big bang assumptions.

Anyway... :)

The problems above can be formulated without a single differential equation and believe it or not - many people haven't heard of the Riemann hypothesis - including many math teachers in economically developed countries.

11. Jun 30, 2009

### Petek

See here for a list of unsolved math problems, some of which can be described as little-known.

12. Jun 30, 2009

### gel

The Gaussian correlation conjecture.

If X is a joint-normal random variable in Rn, A,B are convex and symmetric (so A=-A, B=-B) sets in Rn, then

$$P(X\in A\cap B) \ge P(X\in A)P(X\in B).$$

13. Jul 1, 2009

### Dragonfall

P vs NP and Riemann are both well known to anyone with a bit of math experience. I'm asking for something more esoteric. No god damn angels.

Last edited: Jul 1, 2009
14. Jul 1, 2009

### Dragonfall

Thanks for an actual reply. No angels dancing on pins here.

15. Jul 1, 2009

### CRGreathouse

Guy's Unsolved Problems in Number Theory has more if you're interested. I think he has at least one analog for (an)other field(s).

16. Jul 1, 2009