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oxeimon
  • Member for 11 years, 11 months
  • Last seen more than a month ago
  • Princeton, NJ, United States
18 votes
Accepted

Can a basis for a vector space $V$ can be restricted to a basis for any subspace $W$?

17 votes
Accepted

seeing the differential dx/y on an elliptic curve as an element of the sheaf of differentials

16 votes
Accepted

Intuition in studying splitting and ramification of prime ideals

14 votes
Accepted

Is the real number $\sqrt{6}$ in $\mathbb{R}$ equal to the 5-adic number $\sqrt{6}$ in $\mathbb{Q}_5$?

13 votes
Accepted

What does "span" looks like in infinite dimensional spaces?

12 votes

If $H,K⊲G$ and $H∩K = \{1_G\}$, then all elements in $H$ commute with all elements in $K$

11 votes

Why study integrality?

9 votes

If G acts on X, show that there must be a fixed point for this action. Please help.

9 votes

How come the function and the inverse of the function are the same?

8 votes
Accepted

How to understand the set of permutation representations of a group $G$?

8 votes
Accepted

Is $C[0,1]$ larger than $\mathbb R$?

8 votes
Accepted

Why is the fundamental group a sheaf in the etale topology?

8 votes

What is the abelianization of $SL(2,\mathbb{Z}_p)$?

7 votes

Is it possible that $\pi$ is finite in other numerical bases?

7 votes
Accepted

N/C theorem : If $\Psi$ is a homomorphism, then $N(H)/ C(H) ~\approx~ \Psi[N(H)]$. Is $\Psi[N(H)]$ a subgroup of $\operatorname{Aut}(H)$

7 votes
Accepted

$\operatorname{Aut}(A_4)\simeq S_4$

7 votes
Accepted

Problem I.3.13 in Hartshorne - Follow Up

6 votes
Accepted

Does there exist a "Möbius cloth"?

6 votes
Accepted

Subgroups of $\mathbb{R}$ generated by two elements

6 votes

Determine if $\phi (g)=g^{-1}$ is a homomorphism.

6 votes
Accepted

Why do we care whether a functor is representable?

6 votes

"Vectors aren't really numbers" - how sound is that statement?

6 votes
Accepted

What's the "easiest" closed 3-manifold with a nonabelian fundamental group?

6 votes
Accepted

Generators of $\mathbb{Z} \times \mathbb{Z}$

6 votes
Accepted

Definition of finite-sheeted covering

6 votes
Accepted

Defining maps from modules over different rings

5 votes
Accepted

Show G has a normal subgroup of a given index

5 votes

Isotrivial but non-trivial family of elliptic curves

5 votes
Accepted

Etale after base change

5 votes

Let $X$ be a scheme satisfying $(*)$, then is any integral closed subscheme $Y$ determined by its topological space?

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