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blancket
  • Member for 2 years, 9 months
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9 votes
1 answer
850 views

Galois group of $x^5-x-1$ over $\Bbb Q$

7 votes
2 answers
259 views

$\pi_1(A,x_0)$ acts on the long exact sequence of homotopy groups for $(X,A,x_0)$

7 votes
1 answer
285 views

Bott Tu Exercise 6.14, integration along the fiber

6 votes
1 answer
61 views

Weighted projective plane as a quotient of $\Bbb CP^2$

6 votes
1 answer
268 views

Fundamental class of a surface

5 votes
2 answers
85 views

$S^2$ is not a countable union of embedded circles $S^1$

5 votes
1 answer
138 views

Explicit homotopy on showing that $\pi_n(X,x_0)$ is abelian for $n \geq 2$

5 votes
1 answer
264 views

Theorem 9.13 in Rudin's Real and Complex Analysis

5 votes
1 answer
212 views

$\sum_{j=1}^n \frac{\partial}{\partial x_j} (\text{cof}(Df))_{ij}=0$ for a $C^\infty$ function $f:\Bbb R^n\to \Bbb R^n$

5 votes
0 answers
75 views

An embedding of $U(n)\to \text{Spin}^c(2n)$

5 votes
1 answer
157 views

Oriented Grassmann is a $2$-sheeted covering space of Grassmann

5 votes
1 answer
152 views

Two definitions of singular cohomology

5 votes
1 answer
102 views

Milnor, Lectures on the h-cobordism theorem, proof of Theorem 3.4

5 votes
1 answer
80 views

Is it true that $\text{Ext}(A,\Bbb Z)=\text{Ext}(A_{tor},\Bbb Z)$ for any abelian group $A$?

4 votes
0 answers
52 views

Intersection number of complex curves in a complex surface

4 votes
1 answer
200 views

Real $2n$-plane bundle with a complex structure is a complex $n$-plane bundle

4 votes
1 answer
125 views

If $(M,g)$ is a Riemannian manifold and $S$ is a regular level set of $f:M\to \Bbb R$ then $\text{grad}f|_S$ is nowhere vanishing

4 votes
1 answer
116 views

Hopf invariant depends only on the homotopy type

4 votes
2 answers
93 views

Question about the proof of Theorem 3.1 in Morse Theory – Milnor [duplicate]

4 votes
1 answer
170 views

Why can the divergence be defined equivalently as ${\rm div}(X)(x)=\sum_j \langle\nabla_j X,e_j\rangle_x$ and $d(i_X dV)=({\rm div}X)dV$?

4 votes
0 answers
120 views

Recovering a covering space via monodromy representation

4 votes
2 answers
93 views

Can $S^k$ be embedded in $S^n$ for all $k>n$?

4 votes
1 answer
186 views

Homotopy type of $\Bbb CP^2 - \Bbb RP^2$

4 votes
2 answers
67 views

If $G$ is a finite subgroup of $GL_n(C)$ then there is a polynomial $f\in C[x_1,...,x_n]$ such that $f(gv)=f(v)$

4 votes
1 answer
93 views

If $\mathrm{Ext}^n_R (M,R/\mathrm{rad}(R))=0$ for all $n\geq 1$, then $\mathrm{Ext}^n_R (M,N)=0$ for all $n\geq 1$.

4 votes
2 answers
136 views

Condition for $L^r(\mu)=L^\infty(\mu)$ where $\mu(X)=1$

4 votes
1 answer
156 views

Postnikov tower of a CW complex is unique up to homotopy equivalence

4 votes
1 answer
314 views

Examples of nicely shrinking sets (Rudin)

3 votes
0 answers
91 views

Relative Mapping Cylinders

3 votes
2 answers
140 views

Universal cover of a space with cell attached

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