Ralph's user avatar
Ralph's user avatar
Ralph's user avatar
Ralph
  • Member for 13 years, 5 months
  • Last seen more than 9 years ago
10 votes
Accepted

Epimorphisms and free submodules

9 votes
Accepted

Is there an $A$ such that $B$ injective iff 1st Ext functor vanishes?

9 votes

What is the "ray" in ray class group?

9 votes
Accepted

On the difference between a projective chain complex and a level-wise projective chain complex

9 votes

Homology of a certain group

8 votes

The number of conjugacy classes and the order of the group

8 votes

Galois cohomology H^1(Q_p, Z_p(2)) = 0?

8 votes

Applications of Zariski topology outside alg. geometry

8 votes
Accepted

Counting isomorphism classes via extensions

8 votes
Accepted

Principal congruence subgroups of $SL(n, \mathbb{Z})$

8 votes

Proofs of the uncountability of the reals

8 votes

determinants and polynomials in matrices

8 votes
Accepted

Which information can be obtained from Poincaré series ?

8 votes

What if I want to look for a space with vanishing first homology but nonzero fundamental group?

8 votes

Projective Varieties

8 votes

Presentation for a group with an abelian subgroup of index 2

8 votes
Accepted

Transgressions commute with the Steenrod operations on the base and fiber in a central group extension?

8 votes
Accepted

Mistake in Wikipedia Entry "Coalgebra"

7 votes
Accepted

entire functions of one complex variable with prescribed value and order.

7 votes
Accepted

Derived Series of Pro-p groups

7 votes

"Lie algebra" for a general group ?

7 votes
Accepted

Is a polynomial ring integral over this subring ?

7 votes

Why doesn't this group have a name?

7 votes

isomorphic spectral sequences => quasi-isomorphic filtered chain complexes?

7 votes

Why are ring actions much harder to find than group actions?

7 votes

How to work with co-multiplication?

7 votes
Accepted

Lists of small groups

7 votes

cohomology of BG, G compact Lie group

7 votes

An example of a beautiful proof that would be accessible at the high school level?

7 votes

Is $\mathbb{Z}_p$ flat $\mathbb{Z}_pG$-module for a finite $p$-group $G$?