1,725 reputation
526
bio website www-ian.math.uni-magdeburg.de/…
location Magdeburg, Germany
age 31
visits member for 3 years, 4 months
seen Mar 31 at 2:25

I am an Australian mathematician.


Jun
21
comment Sufficient conditions for Liouville theorem
@Gortaur If a function is bounded above (or below) on $\mathbb{R}^n$ then it achieves its maximum (or minimum) on it also (not at infinity).
Jun
21
comment Sufficient conditions for Liouville theorem
@Theo Thanks for the reference. I was aware of this proof but not aware of the reference!
Jun
21
comment Sufficient conditions for Liouville theorem
@Gortaur, apologies, it wasn't clear to me that you could not find the original reference. The proof of the classical version is quite simple and does indeed follow from the maximum principle (in a sense).
Jun
21
comment Sufficient conditions for Liouville theorem
If you are just after the classical version, then you may be satisfied with Theorem 3.5 from Gilbart and Trudinger.
Jun
21
comment Sufficient conditions for Liouville theorem
You might want to improve the question by stating the excact version of Liouville's theorem you are referring to (there are several), which script or book which you are reading, and a statement of the strong maximum principle.
Jun
20
comment Collatz finally solved?
This just appeared in a newspaper here in Germany as a purported solution. I'm sorry to read that it is so plainly false :(.
Jun
11
awarded  Nice Answer
Jun
2
comment How to integrate by parts in spherical coordinates
Are you still looking for some more information about this Nanoc? If you could explain what is sill missing for you, perhaps I could help.
Jun
1
answered Can I use Ravi Vakil's way of learning for elementary subjects?
May
31
comment Coordinate-free techniques in Lagrangian mechanics
@Jor I take your point, but would like to also point out that if Akater is indeed still learning English and used the word inadvertently, then it is much better to become aware of standard (and dare I say it, correct) usage. I have yet to hear "somewhy" spoken.
May
31
comment Coordinate-free techniques in Lagrangian mechanics
@Joriki, Akater: It's not really a word. The expression you are looking for is "for some reason".
May
30
comment How to prove that the Cantor ternary function is not weakly differentiable?
The last part of the argument doesn't seem correct. The function $f(x) = 1/2$ for $x\in[0,1/2)$ and $f(x) = 2x-1/2$ seems to be a counterexample to the last claim.
May
30
comment Does there exists a absolute measure for growth-rate of a function?
This question is ill-posed: what is your idea of absolute growth?
May
26
comment Constructive proof of boundedness of continuous functions
Is this supposed to be a proof?
May
26
revised Is compactness a stronger form of continuity?
correction
May
26
suggested suggested edit on Is compactness a stronger form of continuity?
May
26
accepted An elementary integral inequality
May
24
comment An elementary integral inequality
Right. That's one point. (Well, actually two points.) The other is that we may be interested in an inequality which holds only on a fixed interval. Your idea still works, in a way, since then we can continue to perform a "limiting" argument through scaling. Then it will depend on the scaling of $A$ and $\alpha$. This is kind of what I was getting at.
May
23
comment An elementary integral inequality
Yes I am vaguely aware of the families of reverse H\"older-type inequalities. I thought they might be overkill here, but you could very well be on to something---the extremals are well-studied and should yield something about best constants.
May
23
comment An elementary integral inequality
Interesting. I wonder about the class $\alpha\in H^2$ say with $\int |\alpha''|^2 > 1$.