1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Convexity of a set

  1. Jan 15, 2012 #1
    A set is convex if it's additive and divisible. To find out the convexity you just pick any two points and draw a tangent line. If the line lies within the area - voila, the set is convex. Similarly, if the set is nonconvex, you just show that a part of any tangent line can lay outside of the set.

    But in the case of nonconvexity, how do I show that it is also nonadditive and nondivisible?

    I've got a set that looks like a flat donut where the donut hole is not a part of the set. I already showed that the set is nonconvex by drawing a tangent line. I do struggle to show (without complex proofs), that the set is also nondivisible and nonadditive.

    Any help is greatly appreciated.
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?