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!

C^infty question

  1. Nov 13, 2005 #1
    Suppose h and h o f are both C^infty on f(U) and U correspondingly, with U an open set. Assume now that f(U) is open. Is f C^infty on U? Does anyone have a counter example?

    I've edited the question so that it would actually make sense.
    Last edited: Nov 13, 2005
  2. jcsd
  3. Nov 13, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper

    trivially false. take h constant.
  4. Nov 13, 2005 #3
    How very stupid of me. Thank you.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?