# Problems and conjectures that have positive practical consequences for society, once solved

This question made me think a bit about how mathematics can be used in such a way that society benefits from it.

I think there are quite a lot of good answers to the aforementioned question. Still, it seems to me that most of the ways to do mathematics "for good" involves doing some sort of applied mathematics, which means you often have to worry about other things rather than the mathematics itself. For me, however, part of the appeal to mathematics stems from the fact that you can work on a problem without having to resort to making observations of "the real world". I guess it's a form of escapism, it's just you and the problem and while your working on it, there aren't a lot of other things on your mind.

Even though the pursuit of solving a purely mathematical problems can be very stimulating and satisfying if you manage to solve it, I sometimes wish that I could work on something of which I would know it would have a positive impact on society. Sure, you know that there's a chance it will be applied to solve a problem in the empirical sciences, but you don't know that for sure. Hardy didn't know his contributions to number theory , which he did not consider to be useful ("Nothing I have ever done is of the slightest practical use"), turned out to come in very handy when designing cryptographic algorithms (See the RSA algorithm).

I was wondering if there are any purely mathematical problems and conjectures of which it known to have a positive impact on society, once they are solved. By a "mathematical problem" I don't mean "Try to find ways to approximate the solution to some set of partial differential equations more quickly, because it would be useful to predict the weather". That's too vague. I'm talking about genuine, purely mathematical problems and conjectures. Please describe exactly how the resolution of the problem and/or conjecture would be of any "good" to society.

• In my opinion this is extremely subjective and should be closed. Moreover, it is essentially impossible to answer; we can never know the net effect of anything. For example, dynamite was used to kill plenty of people; but it's also helped us perform tasks that used to have to be done with manual labor. But is that a good thing if people lost their jobs because of it? And so on. Mathematics and its applications provide us with tools (physical, algorithmic, etc.). Any tool can used for "good" or for "bad" ends; that is up to us. There is no (and cannot be) a direct line math $\rightarrow$ good. – Zev Chonoles Dec 7 '11 at 16:27