149 reputation
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bio website brunogalvan.it
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visits member for 3 years, 2 months
seen Feb 19 at 19:06

Jul
2
awarded  Curious
Jan
4
comment Conjecture: the function $d(x, y):=\frac{||x-y||}{\max(||x||, ||y||)}$ is a distance
But this inequality does not seem to be easier to prove than the triangle inequality
Jan
2
comment Conjecture: the function $d(x, y):=\frac{||x-y||}{\max(||x||, ||y||)}$ is a distance
I agree @coffeemath, but we have not yet a rigorous proof, and this is strange, due to the "apparent" semplicity of the problem.
Jan
1
comment Conjecture: the function $d(x, y):=\frac{||x-y||}{\max(||x||, ||y||)}$ is a distance
Yes, I do not think it is a trivial problem
Jan
1
awarded  Commentator
Jan
1
comment Conjecture: the function $d(x, y):=\frac{||x-y||}{\max(||x||, ||y||)}$ is a distance
I already know this. The difficult case is $||x||\leq ||z|| \leq ||y||$.
Jan
1
revised Conjecture: the function $d(x, y):=\frac{||x-y||}{\max(||x||, ||y||)}$ is a distance
deleted 135 characters in body
Jan
1
asked Conjecture: the function $d(x, y):=\frac{||x-y||}{\max(||x||, ||y||)}$ is a distance
Sep
18
accepted What is the closure of the Laplacian on $L^2(0, \infty)$ with domain $D(\Delta):=C^\infty_0(0, \infty)$?
Sep
10
comment What is the closure of the Laplacian on $L^2(0, \infty)$ with domain $D(\Delta):=C^\infty_0(0, \infty)$?
Thank you brom. I have to say that I must study better Sobolev spaces in order to fully undertand your answer.
Sep
9
comment What is the closure of the Laplacian on $L^2(0, \infty)$ with domain $D(\Delta):=C^\infty_0(0, \infty)$?
Yes, ************
Sep
8
comment Is $(-\infty, 0] \cup (1, \infty)$ dense in $\mathbb{N}$?
Dense in R, as written in the title, or in N, as written in the body?
Sep
8
asked What is the closure of the Laplacian on $L^2(0, \infty)$ with domain $D(\Delta):=C^\infty_0(0, \infty)$?
Jul
11
comment Prove the equation: $\frac{2}{\pi} \int_0^\infty \frac{\cos kr - ak \sin kr}{k^2a^2 +1} \ldots $
Yes, it would be.
Jul
5
awarded  Promoter
Jul
4
revised Prove the equation: $\frac{2}{\pi} \int_0^\infty \frac{\cos kr - ak \sin kr}{k^2a^2 +1} \ldots $
deleted 206 characters in body; edited title
Jul
4
revised Prove the equation: $\frac{2}{\pi} \int_0^\infty \frac{\cos kr - ak \sin kr}{k^2a^2 +1} \ldots $
deleted 206 characters in body; edited title
Jul
3
revised Prove the equation: $\frac{2}{\pi} \int_0^\infty \frac{\cos kr - ak \sin kr}{k^2a^2 +1} \ldots $
edited title
Jul
3
revised Prove the equation: $\frac{2}{\pi} \int_0^\infty \frac{\cos kr - ak \sin kr}{k^2a^2 +1} \ldots $
added 2 characters in body
Jul
3
asked Prove the equation: $\frac{2}{\pi} \int_0^\infty \frac{\cos kr - ak \sin kr}{k^2a^2 +1} \ldots $