bio  website  mate.dm.uba.ar/~aldoc9 

location  Buenos Aires  
age  41  
visits  member for  5 years, 8 months 
seen  7 hours ago  
stats  profile views  20,249 
1d

awarded  Guru 
Jun 23 
comment 
Do representations of the universal enveloping algebra $\mathrm{U}\mathfrak{su}_2$ retain the Hopf algebra structure?
In what way is your $U_J\mathfrak{su}_2$ an algebra? 
Jun 23 
comment 
Do representations of the universal enveloping algebra $\mathrm{U}\mathfrak{su}_2$ retain the Hopf algebra structure?
There are no Hopf algebras which are simple as algebras (except the ground field, of course), precisely because of the existence of the counit. On the other hand, there is no finite dimensional Hopf algebra over a field of characteristic zero with a nonzero primitive element. 
May 28 
awarded  Necromancer 
May 27 
comment 
Example of a $G$sphere that is not a $G$representation sphere
@QiaochuYuan, can a finite group not fix a smooth structure? 
May 27 
comment 
The construction of the 257gon
@FranzLemmermeyer, thanks! Do you know what the tables appearing in pictures 8 to 4 (counting from the last) are? 
May 26 
comment 
What is the exterior derivative intuitively?
@FallenApart, ah. No , I do not mean that $\Omega^1(M)$ is the module of Kähler differentials of $C^\infty(M)$ (mostly, because it isn't! :) ) The operator $d:C^\infty(M)\to\Omega^1(M)$ can be characterized in terms of its functorial properties. This is surely done in detail in the book Natural Operations in Differential Geometry by Kolar, Michor and Slovak. 
May 26 
comment 
What is the exterior derivative intuitively?
@FallenApart, I don't understand exactly what statement you mean. 
May 14 
awarded  Good Answer 
May 13 
comment 
Homotopy type of embeddings of circle in the plane
My guess is because the group of selfhomeos of the circle has contractible identity component (a homeo lifts to a map $\mathbb R\to\mathbb R$, and the latter is a strictly increasing or decreasing function which you can deform to a linear one) 
May 13 
comment 
Homotopy type of embeddings of circle in the plane
What do you mean by embedding,exxactly? If the maps are injective then you have only two contractible components, no? 
May 3 
comment 
Singular projective variety where the Cartan homomorphism is not an isomorphism?
The Hilbert series in that situation converges to a rational function which can be evaluated at everything which is not a pole. 
May 3 
comment 
Singular projective variety where the Cartan homomorphism is not an isomorphism?
You talk about a linked question in your question but there is no link? 
Apr 23 
comment 
When does Vopěnka's principle hold?
What is $0^\sharp$? : 
Apr 23 
comment 
unfolding as resolution
I've always associated that with blowups. 
Apr 23 
comment 
Must an algebraic variety with trivial tangent bundle be an abelian variety?
What a beautiful theorem. 
Apr 20 
revised 
When is an algebra of commuting matrices (contained in one) generated by a single matrix?
deleted 1 character in body 
Mar 28 
comment 
Are there any Algebraic Geometry Theorems that were proved using Combinatorics?
Mathematical truth has very few sources. Arithmetic is one, combinatorics is another. Most things have a genealogy which goes all the way to these true Adam and Eves, through a surprisingly short chain of begats. 
Mar 24 
awarded  Good Answer 
Mar 17 
awarded  Nice Answer 