MHB How Does Sobolev Space Boundedness Relate to Different Norms in $R^n$?

  • Thread starter Thread starter Danny2
  • Start date Start date
  • Tags Tags
    Space
Click For Summary
The discussion centers on the relationship between Sobolev space boundedness and different norms in R^n, specifically addressing the inequality relating norms for functions in Sobolev spaces. It highlights that for given parameters r, s, and t, there exists a constant C that connects the norms of functions across these spaces. The importance of the domain of the function f is emphasized, noting that it affects the analysis, particularly distinguishing between integration on different domains like the torus versus R^n. The conversation indicates that understanding the context of the problem is crucial for tackling the inequality effectively. Overall, the discussion underscores the need for clarity on the function's domain to proceed with the problem.
Danny2
Messages
3
Reaction score
0
If $ r<s<t $ then for any $ ϵ>0 $there exists $ C>0 $ such that $ ∥f∥_{(s)}≤ϵ∥f∥_{(t)}+C∥f∥_{(r)} $for all $f∈H_t $

Can you please tell me how to start thinking of this problem? I really feel stuck and don't know where to start!
 
Physics news on Phys.org
Welcome, Danny! (Wave)

Some information is missing in the problem statement. What is the domain of $f$?
 
$f$ is a tempered distribution
 
What I mean is this: $f\in H^t(X)$ for some space $X$ -- what is $X$? It makes a difference, since, e.g., integration on the torus is different from integration on $\Bbb R^n$.
 
$R^n$
 
We all know the definition of n-dimensional topological manifold uses open sets and homeomorphisms onto the image as open set in ##\mathbb R^n##. It should be possible to reformulate the definition of n-dimensional topological manifold using closed sets on the manifold's topology and on ##\mathbb R^n## ? I'm positive for this. Perhaps the definition of smooth manifold would be problematic, though.

Similar threads

  • · Replies 0 ·
Replies
0
Views
2K
Replies
2
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 13 ·
Replies
13
Views
4K
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
Replies
1
Views
1K
Replies
5
Views
2K