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R_D
  • Member for 7 years, 11 months
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11 votes
0 answers
267 views

How to prove this is a fibre bundle?

10 votes
4 answers
2k views

Is this dual pairing the same as the inner product?

10 votes
1 answer
432 views

Equivalence of two definitions of Spin structure

9 votes
0 answers
137 views

Is this covering group $G'$ of $G$ unique?

9 votes
1 answer
2k views

Is the action of a finite group always discontinuous?

9 votes
2 answers
2k views

Universal cover of $\mathbb R^2\setminus\{0\}$

8 votes
1 answer
193 views

Is there a name given to a space whose first three Stiefel-Whitney classes vanish?

7 votes
0 answers
231 views

Proving that the given map has the path lifting property

7 votes
1 answer
263 views

Is Homeo$(X)$ metrizable?

7 votes
1 answer
524 views

If the fibers of a quotient map are all discrete, is this map a covering map?

6 votes
3 answers
411 views

Definition of a Manifold from Guillemin Pollack

6 votes
1 answer
537 views

Why is the rank of a locally free sheaf same everywhere if $X$ is connected?

6 votes
1 answer
240 views

$\phi:\mathcal F\rightarrow \mathcal G$ is an isomorphism if there is an open cover on which $\phi(U)$ is an isomorphism.

5 votes
2 answers
1k views

$f:X\rightarrow Y$ is a closed immersion iff $f:f^{-1}(U_i)\rightarrow U_i$ is a closed immersion.

5 votes
0 answers
673 views

Definition of geometric vector bundle from Hartshorne

5 votes
1 answer
76 views

What is the closure of $S^1\times \mathbb{Z}$ in Homeo$(S^2\times \mathbb{R})$?

5 votes
1 answer
78 views

Where have we used that $G$ is a compact Lie group?

5 votes
1 answer
305 views

On lifting an action of $G$ on $X$ to an action of $G'$ on $\tilde{X}$.

5 votes
3 answers
347 views

Is the action of $\mathbb Z$ on $\mathbb R$ by translation the only such action?

5 votes
2 answers
321 views

What are the direct summands in $\mathbb{Z}^n$?

5 votes
2 answers
136 views

If $f:X\rightarrow Y$ has the path lifting property the so does $f|_A$?

5 votes
1 answer
106 views

If $G$ is a group of isometries of $X$ then prove that $X/G$ and $X/\bar{G}$ are homotopically equvalent

5 votes
3 answers
463 views

What is the intuition behind saying that the nilradical is the intersection of prime ideals?

5 votes
1 answer
155 views

Is there a way to calculate the sum of absolute values of the roots of a cubic polynomial without actually computing the roots?

5 votes
1 answer
390 views

Is the quotient $X/G$ homeomorphic to $\tilde{X}/G'$?

5 votes
1 answer
706 views

On the definition of a reductive group.

5 votes
2 answers
558 views

How to write the commutator subgroup in terms of the generators of the group?

4 votes
4 answers
545 views

Proving a symmetric Cauchy matrix is positive semidefinite

4 votes
3 answers
208 views

Perron Frobenius theorem for matrices with entries from $\{-1,0,1\}$

4 votes
2 answers
150 views

If $A$ and $B$ have non-negative eigen values then can we conclude that $A+B$ has non-negative eigen values?

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