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Professor Receives Praise for 40 Year Old Problem

An anonymous reader writes "The Kansas City Star is reporting that Steven Hofmann is in line to receive accolades from his peers this coming year in Madrid, Spain for solving a mathematical problem that has baffled mathematicians for over 40 years. Hofmann, a professor at the University of Missouri-Columbia, solved the 3 dimensional version of the 'Kato problem for divergence form elliptic operators with Gaussian heat kernel bounds' (say that 10 times fast!). From the article: 'For three years, starting in 1996, Hofmann worked on the problem for two to eight hours every day [...] Hofmann said the solution could allow mathematicians to better describe the behavior of waves traveling through a medium that changes over time. But beyond that, he said, it is impossible for him to explain all the real-world applications.'"

11 of 42 comments (clear)

  1. A nice little article by Starker_Kull · · Score: 4, Interesting

    It really doesn't explain much about the problem, but it does do a nice job of explaining how some people wind up in mathematics:

    "Hofmann majored in math, he said, "because it was the path of least resistance." While his friends were writing history papers that were many pages long or spending hours in a computer lab, "all I had to do was solve math problems, and it was something that came to me naturally," he said.

    "By the time you get to graduate school, even if it comes naturally, it gets hard, and that is when you begin to develop a skill to go with the ability.""

    It's nice to see an article about a mathematician that isn't a "look at the freaky math guy" or "look at the useless thing we're paying people to do" kind of writeup, but just about someone who was enjoyed playing with mathematics, and has done well by it.

    Anyone have a better explanation of what he did or where it fits in? Is it more theoretical or applied? What stuff is it related to?

    1. Re:A nice little article by alicenextdoor · · Score: 3, Informative
      The abstract of the paper in question: "We solve the Kato problem for divergence form elliptic operators whose heat kernels satisfy a pointwise Gaussian upper bound. More precisely, given the Gaussian hypothesis, we establish that the domain of the square root of a complex uniformly elliptic operator L = div(A) with bounded measurable coefficients in Rn is the Sobolev space H1(Rn) in any dimension with the estimate Lf2 f2. We note, in particular, that for such operators, the Gaussian hypothesis holds always in two dimensions."

      No, I don't understand it, either! Something tells me this is one of those classic problems that you just can't explain in words of one syllable...

      --
      of course, biting monkeys is not to everyone's taste - Konrad Lorenz
  2. Why applications? by siwelwerd · · Score: 4, Insightful

    Why is the first question about a mathematical breakthrough always "What are the applications?" Why can people not accept that mathematics is interesting in its own right?

    1. Re:Why applications? by mooingyak · · Score: 2, Insightful

      What applications are there for this question?

      --
      William of Ockham had no beard. The most likely explanation is that it was chewed off by squirrels every morning.
  3. Not sure what others would apply it to by jd · · Score: 2, Insightful
    But if the summary of "waves in a changing medium" sums it up, then here are a few ideas. (Please note that if the summary I got is inaccurate or incomplete, then none of these examples would apply):


    • Supersonic and hypersonic aircraft design: The shockwave is a wave (duh!) and the medium it travels through (the air) is certainly changing. This applies to the shock going through the air into the surroundings, so could modify models of aircraft noise.
    • Vibrations within any aircraft: The vibrations are also a wave. The aircraft changes (as a medium) with temperature, also because it uses up fuel (and therefore changes in composition and distortion) but also as a result of the waves (stress in the metal, for example). The same will apply to any vehicle, provided there is sufficient change to the vehicle to be significant.
    • Gravity waves: Gravity alters space, space alters the movement of the gravitational bodies, the gravitational bodies alter the waves.
    • Microwave ovens: The microwaves heat the food. In so doing, you change the composition of the atmosphere through which the microwaves travel, thus absorbing some and potentially causing refraction.

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
  4. Mathematician's are players by isthisorigional · · Score: 5, Funny
    Hofmann, a professor at the University of Missouri-Columbia, solved the 3 dimensional version of the 'Kato problem for divergence form elliptic operators with Gaussian heat kernel bounds'

    Now if that doesn't give him a good pickup line, I don't know what will.

    1. Re:Mathematician's are players by fbjon · · Score: 4, Funny

      Hey baby, would you like to increase my 3-dimensional divergence by heating my kernel bounds?

      --
      True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
  5. Why? It's simple. by John+Nowak · · Score: 3, Insightful

    When people hear of something like this, oftentimes they can feel threatened that someone is so much more intelligent then they are. (If this is true or not, or if intelligence is even quantifiable doesn't matter -- That's how they're feeling.) As a defense, they pose the question "what is this actually good for". They take comfort in that the answer is "not much", hence allowing them to know that at least they're not wasting their time on such useless nonsense, and no matter how "intelligent" the discoverer is, he's still an "idiot" for "wasting his time" on it.

    1. Re:Why? It's simple. by Anti_Climax · · Score: 2, Insightful

      To add to that, all too often it takes just as long to find uses for the solution as finding the solution itself. How long did we have Boolean mathematics before they wer put into use for digital compters? More than 70 years.

      If we find more uses for it, great. If not, we have a better collective grasp of pure mathematics.

      --
      Even people that believe in pre-destiny look both ways before crossing the street.
  6. Re:Nobel prize for physics! by 0xC0FFEE · · Score: 3, Informative

    That's effectively the nearest equivalent except for a few differences. First among them is that the price is given to people _under_ 40. Second the price is given every 4 years. So the Fields is way more difficult to get because of those additional constraints.

  7. Don't ask what it's good for. by Metasquares · · Score: 2, Insightful

    Math is related to itself in so many ways that even the most abstract of problems can have benefits in seemingly unrelated areas. For example, if you can prove a certain bound on the divisor function (lowercase sigma), you'll be able to prove the Riemann hypothesis. These are two seemingly unrelated problems, but solving one will yield a solution to the other.

    There's nothing too impressive about solving a 40 year-old problem, though: Some problems went unsolved for hundreds of years. Still, I can't even understand this problem, let alone attempt a solution at it (and I studied math), so bravo!