User talk:Juan Manuel Marquez Bobadilla

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Also, I moved Juan Marquez to User:Juan Marquez. Please do not write about yourself in the main namespace. jni 18:23, 6 Apr 2005 (UTC)

1 Email address
2 Your edits to 3-manifold
3 Some comments
4 RF
5 Title
6 Zum beispiel
7 Reference
8 Schwarzschild coordinates
9 Links in section headings
10 Area of a circle
11 Totopo
12 Graf

[edit] Email address

Please don't post your email address as an encyclopedia article.--Scimitar ^parley 18:07, 1 September 2005 (UTC)

[edit] Your edits to 3-manifold

Hi Juan,

I'm getting a little concerned about your edits to 3-manifold. For example, do not include information that is inappropriate for a section, e.g. adding Herbert Seifert to the References section. Also, if you add to the Foundation Results section, you should mention what the result is, not just add a link to handle decompositions]; it seems your intent was just to mention that every compact 3-manifold has a Heegaard splitting, so I added that instead. In addition, handle decomposition already exists and is in much better shape. When creating a new article, do not create the title in plural form, e.g. 3-manifold not 3-manifolds. Finally, a handlebody is not a handle. This seems to be a mistake in terminology on handle decompositions and was earlier straightened out on handle decomposition, unless you had some other intent (such as describing how Heegaard splittings arise from handle decompositions, which is well described in Heegaard splitting). In general, it seems to me that you just need to do more exploring of the content before writing a new article. I hope this is constructive advice for you. It's good to have another 3-manifold editor on board.

I haven't had a chance to think about your email, and I don't know when I can get to that. But your research sounds very interesting. I don't think it has been done before, but it sounds like the kind of thing that may have, so I wouldn't take my word for it. --Chan-Ho 18:46, 30 September 2005 (UTC)

[edit] Some comments

Thank you for your edits to mathematical analysis. I have a few general comments. First, is that links should be singular, and it is good if one checks where the links point. Thus, [[sequence]]s is preferred to [[sequences]] and [[series (mathematics)|series]] is preferrred to [[series]].

Also, it is good if you use an edit summary, it is a way of documenting what you changed and very helpful for others checking your contributions or looking at the page history. Thank you, and I hope you like it here. Oleg Alexandrov (talk) 00:15, 29 December 2005 (UTC)

[edit] RF

In topology,

Let $M$ be a manifold. By a round function we mean a function $M\to{\mathbb{R}}$ whose critical points form connected components, each of which is homeomorphic to the circle.

[edit] Title

In calculus, by a round function we mean a scalar function $M\to{\mathbb{R}}$ over be a manifold $M$ whose critical points form one or several connected components, each homeomorphic to the circle $S 1$ , called critical loops.

[edit] Zum beispiel

For example, let $M$ be the torus. Let $K=(0,2\pi)\times(0,2\pi)$ . Then we know that a map $X\colon K\to{\mathbb{R}}^3$ given by

$X(\theta,\phi)=((2+\cos\theta)\cos\phi,(2+\cos\theta)\sin\phi,\sin\theta)\,$

$K(\theta,\phi)= \begin{bmatrix} (2+\cos\theta)\cos\phi\\ (2+\cos\theta)\sin\phi\\ \sin\theta \end{bmatrix}$

is a parametrization for almost all of $M$ . Now, via the projection $\pi_3\colon{\mathbb{R}}^3\to{\mathbb{R}}$ we get the restriction $G=\pi_3|_M\colon M\to{\mathbb{R}}, (\theta,\phi)\mapsto\sin\theta$ whose critical sets are determined by

$\nabla G(\theta,\phi)=({{\partial}G\over {\partial}\theta},{{\partial}G\over {\partial}\phi})(\theta,\phi)=(0,0),$

if and only if $\theta={\pi\over 2},\ {3\pi\over 2}$ .

These two values for $θ$ give the critical sets

X (π / 2,φ) = (2cosφ,2sinφ,1)

X (3π / 2,φ) = (2cosφ,2sinφ, - 1)

which represent two extremal circles over the torus $M$ .

Observe that the Hessian for this function is

Hess(G) =

$\begin{bmatrix} -\sin\theta & 0 \\ 0 & 0 \end{bmatrix}$

which clearly it reveals itself as of $rankHess(G) = 1$ at the tagged circles, making the critical point degenerate, that is, showing that the critical points are not isolated.

[edit] Reference

Siersma and Khimshiasvili, On minimal round functions, preprint [1]

[edit] Schwarzschild coordinates

Good catch, thanks for noticing this! ---CH 23:27, 8 May 2006 (UTC)

[edit] Links in section headings

Hi. Just a comment. One should not use links in section headings, so ==As a functor== better be ==As a functor==. I fixed that one but I thought I would let you know. You can reply here if you have comments. Thanks. Oleg Alexandrov (talk) 03:41, 1 July 2006 (UTC)

And one should not leave too much space between sections either, looks bad. :) Oleg Alexandrov (talk) 03:41, 1 July 2006 (UTC)

[edit] Area of a circle

The area of a circle is the area of the enclosed region. Stating flat out that "a circle has not area" is confusing and at variance with established practice. Disk might more properly describe the enclosed region, but that's a distinction that most people (and most mathematicians) don't bother to make. EdC 06:59, 29 October 2006 (UTC)

[edit] Totopo

If you are going to cancel a redirect, you need to replace it with an article, not just a one-line comment that Totopo is not a Tortilla chip. A better idea would be to add something to the tortilla chip article explaining the difference, there is room for expanision and more people will see it that way, few people are going to search for totopo. And , yes, there are round as well as triangular tortilla chips. Tubezone 04:27, 24 November 2006 (UTC)

Si, entiendo que totopos no son iguales de los tortilla chips, no tuve dudas de eso. La problema es el nuevo articulo que ud hizo falta explicacion de caracteristicas del producto, una oracion que dice que los dos no son iguales no es suficiente. Ellos van a borrar por rapido por razon de faltar contexto si el articulo queda en su condicion del presente. Ud. no hace pruebas matematicas asi, ¿verdad? Tubezone 04:58, 24 November 2006 (UTC)

I don't get who is going to erase

Los adminstradores que revisan los combios

and in math there are some short powerful proofs. Gimme a few hours to expand totopo, thanx--kiddo 05:03, 24 November 2006 (UTC)

Estoy de acuerdo, escriba lo que ud quiere, yo regresare a la pagina a hacer correciones gramaticas si ud hace errores ;-) Tubezone 05:08, 24 November 2006 (UTC)

[edit] Graf

—The preceding unsigned comment was added by Juan Marquez (talk • contribs) 23:46, 8 December 2006 (UTC).

tres discos que descomponen al plano proyectivo y tres toros que descomponen al fibrado trivial

lets look this $\sum$ from afar

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