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

location  Buenos Aires  
age  41  
visits  member for  5 years, 10 months 
seen  yesterday  
stats  profile views  20,537 
1d

awarded  Guru 
Aug
29 
comment 
cup product and Steenrod operations in Serre spectral sequence
What one does have is an algebra isomorphism of the gr of the limit with the E^2 page. In this example one sees exactly what gets lost when passing to the associated graded algebra. 
Aug
28 
comment 
$Ext$algebra generated by $Hom$ and $Ext^1$ as $A_\infty$algebra?
For $N$Koszul modules you do need also the higher products. The cup product on $Ext_A(k,k)$ with $A$ $3$Koszul is in fact zero. (I wrote Koszul but I was think of $N$Koszul :/ ) 
Aug
28 
comment 
$Ext$algebra generated by $Hom$ and $Ext^1$ as $A_\infty$algebra?
This works for Koszul modules, iirc. 
Aug
25 
comment 
Are all separable algebras Frobenius algebras?
(I also implictly assumed you were in a context in which there is a ground ring around; it would certainly help if you emphasized in your question that this is not the case!) 
Aug
25 
comment 
Are all separable algebras Frobenius algebras?
One way to construct this is to look at the subsemigroup $\{0,1\}$ of the multiplicative semigroup of $\mathbb R$ with its induced order, turning it into a category as a poset and as a monoidal category using the semigroup structure. 
Aug
23 
awarded  Nice Answer 
Aug
20 
awarded  Nice Question 
Jul
26 
awarded  Good Answer 
Jul
18 
comment 
Commutative algebra books representing the edge of research
You should subscribe to arXiv announcements on that subject and, if you have access, browse MathSciNet. 
Jul
16 
comment 
Limits of complex projective varieties in the Hausdorff topology on closed subsets of CP^n
Ah. I am sorry. I thought you might be trying to be helpful. My mistake. 
Jul
16 
comment 
Limits of complex projective varieties in the Hausdorff topology on closed subsets of CP^n
But homogeneous polynomials do not "take values" on points of projective space. 
Jul
10 
comment 
Lie algebra cohomology with values in the ring of smooth functions of a $G$manifold
The original version looked intriguing :) 
Jul
10 
comment 
Lie algebra cohomology with values in the ring of smooth functions of a $G$manifold
Your cocycles are just smooth maps? They are usually linear. 
Jul
6 
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? 