Augusto Matteini

 Mathematics

Associated with Math.SE; for both general discussion & math qu...
Oct 15, 2023 18:07
Does anyone know a good text reference for fuchsian and quasi-fuchsian group? I'm interested in the basics for studying Teichmuller theory, I found the handbook of Papadopoulos but they seems a little bit overwhelming for a start
Jul 26, 2023 15:50
Does anyone know how does he conclude with the implicit map theorem? I don't understand why g has to be equal to f. After that it is clear but I don't understand neither how does he know that it should have g(y)=f(y) neither why the condition implies the equality of the 2 functions thank you.
Jul 26, 2023 15:50
Mar 19, 2022 19:38
It's just that Heine Borel is such a way of life that as soon as i saw open and compact it had to be "him" haha
Mar 19, 2022 19:38
Thank you
Mar 19, 2022 19:37
saying that being compact means closed and limited is a contraddiction to being open and compact only if i use that the only clopen set in Rn is Rn itself
Mar 19, 2022 19:36
yeah that was dumb lol you are right
Mar 19, 2022 19:30
In all the answers that I fount related to submersion of compact manifold in $R^{n}$ they always conclude using connection of $R^{n}$ (ie math.stackexchange.com/questions/1995022/…) Now, while of course it does not change much, would it be wrong arguing that f(M) must be compact and open but this is against Heine Borel?
Mar 12, 2022 06:51
(Of course I could prove that the torus is compact as closed and limited, product of compact... but I'm interested if I'm doing something missleading when dealing with equivalence class)
Mar 12, 2022 06:50
When i view the torus as $\mathbb{R}^{2}/\langle(x+1,y),(x,y+1)\rangle$ can i just say that it is compact using that the restriction of the projection to $[0,1]\times[0,1]$ is surjective and continuous? The morale of this is that it is a fundamental domain but I don't really need it for a "weak" argument related to just compacteness, do I?
Feb 19, 2022 10:28
you wrote it yourself
Feb 19, 2022 10:28
Friends lie, Girlfriends lie, Algebra does not
Feb 19, 2022 10:28
in that case you can have more than 1 answers only if sqrt(b)=-sqrt(b) as you wrote hence b=0
Feb 19, 2022 10:20
that thing is 0 because a=sqrt(b) but you already know that, it's literally your first line
Feb 19, 2022 10:20
you can't assume that from what you have wrote
Feb 19, 2022 10:20
the "from this" we can say it's just false
Feb 19, 2022 10:13
@user123456789 Just ask; don't ask to ask
Feb 19, 2022 10:00
I can use the classic Cauchy-inequality to prove the theorem but I would like to understand from where that integral cames up
Feb 19, 2022 09:59
I can just "copy" the proof that the coefficient of a Fourier series are in that form and adapt it to Homogeneus Expansion for holomorphic function?
Feb 19, 2022 09:57
Feb 19, 2022 09:57
Any hint on how to prove the following integral equality? I'm getting lost because it seems to me that we are mixing some Cauchy integral formula with some Fourier Series but I've never seen anything similar in class
Oct 28, 2021 17:41
ok im dumb, p* is always injective
Oct 28, 2021 17:35
Or if it is not that how can i obtain a surjective homomorphism from $H$ having one from $C$? For how it is left is should be trivial but I could not find any argument
Oct 28, 2021 17:34
thank you in advance
Oct 28, 2021 17:34
Could anyone try to help me understand why in the proof of theorem 3.2 page 13 (here numdam.org/item/10.5802/aif.2098.pdf) is it so obvious that $\pi_{1}(C)\simeq H$? For what I have understood it should be $p*(\pi_{1}(C))\simeq H$
Oct 25, 2021 22:10
@leslietownes a bless in disguise
Oct 25, 2021 21:49
Hi, a little group theory problem i got stuck all day and cant seem to be able to solve it. I have a group and i'm supposing that it is left orderable. If I know that $yhy^{-1}=h^{-1}$ and that $h^{-k}<y^{2}<h^k$ and $h^{-k}<y^{-2}<h^{k}$ with $h>1, k>0$ how can I show that $yhy^{-1}>1$? I've tried for a while to work it out with "bare hands calculation" but I think I'm missing something
Oct 6, 2021 10:49
@BalarkaSen I agree
Oct 6, 2021 09:04
Oct 6, 2021 09:00
Hi @BalarkaSen, no never seen a Siefert surface of the trefoil knot?
Oct 5, 2021 20:04
while Munkres is "too easy"
Oct 5, 2021 20:03
but I only know hatcher from Algebraic Topology and his 3-manifold notes are quite an advanced starting point (at least for my pov) and don't even cover this topic
Oct 5, 2021 20:02
I mean if you have any reference book I will be delighted to stop bothering you
Oct 5, 2021 20:02
when it gets in technicality I agree that I don't have the backround but I was more interested in the algebraic flavour of the paper
Oct 5, 2021 20:01
Some parts, I don't have the arrogance to say that I'm good in 3-manifolds
Oct 5, 2021 20:00
But it's just an example
Oct 5, 2021 20:00
I don't have the appropriate background to work out the example alone
Oct 5, 2021 19:59
It's an example in a paper
Oct 5, 2021 19:58
I wish i knew some topologist haha
Oct 5, 2021 19:58
what is a meridional slope? is it a circle? half a circle? I literally never heard of it, only heard of slope for a line
Oct 5, 2021 19:57
last question I guess
Oct 5, 2021 19:57
Ok, sorry
Oct 5, 2021 19:56
Is this what they mean?
Oct 5, 2021 19:56
Oct 5, 2021 19:56
Oct 5, 2021 19:56
I was trying to understand the following example from a paper
Oct 5, 2021 19:56
I will repost something that i had already asked but I can't work it out alone, sorry
Oct 5, 2021 17:17
english is not my mother tangue and I've always encountered slope as in a line or a mountain, I would not know what use I should make of meridional slope
Oct 5, 2021 17:16
Or meridional slope is just the whole circle? I'm not sure about the wording "slope"
Oct 5, 2021 17:14
At least they intersect once I guess..