Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 9652

Continuum theory, point-set topology, spaces with algebraic structure, foundations, dimension theory, local and global properties.

4 votes

Continuity of $\arg\min$

The answer is no (also for the question with $\epsilon$). Here is a counterexample: Consider $m=n=1$ and $$ f(x,y) = (x^2-1)^2 + yx. $$ For $y>0$ there is a unique minimizer to $\min_x f(x,y)$ whi …
Dirk's user avatar
  • 12.7k
3 votes

Generalized Stokes' theorem

As said in the article, you find these results in book on geometric measure theory. Maybe "Geometric Integration Theory" by Krantz and Parks can be of help. Theorem 6.2.12 (not in the preview on Googl …
Dirk's user avatar
  • 12.7k
18 votes

Notions of convergence not corresponding to topologies

Since that question popped up on the screen again I add something to the list (although I am pretty late to the party): The fact that pointwise almost everywhere convergence is not topological is nice …
Dirk's user avatar
  • 12.7k
19 votes
4 answers
8k views

Unique limits of sequences plus what implies Hausdorff?

It is known that there are non-Hausdorff spaces which admit unique limits for all convergent sequence (see here) and it is also known that unique limits for nets implies Hausdorff. What I am wonderin …
Dirk's user avatar
  • 12.7k
4 votes

How does the parity of $n$ affect the properties of $\mathbb{R}^n$?

The hairy ball theorem states that there is no nonvanishing continuous tangent vector field on even-dimensional spheres.
6 votes
Accepted

Fréchet L-Spaces

I think that these spaces don't go under the name of $L$ spaces anymore. Actually, I am not sure if there is a consensus on how these structures are called today. A good place to start is the fairly r …
Dirk's user avatar
  • 12.7k
11 votes

Is the boundary $\partial S$ analogous to a derivative?

Another, not too mathematical, analogy comes from image processing. There you can consider an image $u$ as a real valued function on a rectangle, say. A basic method for edge detection is to calculate …
Dirk's user avatar
  • 12.7k