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Marion
  • Member for 9 years, 7 months
  • Last seen more than a week ago
15 votes
13 answers
7k views

How to explain the formula for the sum of a geometric series without calculus?

14 votes
1 answer
6k views

$S^2=SO(3)/SO(2)$. Does this mean that $S^2 = SU(2)/U(1) $?

13 votes
1 answer
2k views

Physicist trying to understand GIT quotient

7 votes
1 answer
555 views

$q$-series and modular forms

7 votes
2 answers
6k views

Fundamental group of $\mathbb{R}^n\backslash \{0\}$

6 votes
2 answers
2k views

Parallel transport of a vector in hyperbolic space, specifically in $\mathbb{H}$

5 votes
1 answer
1k views

If $\phi: M_1 \to M_2$ a diffeomorphism between diff. manifolds, prove that if $M_2$ is orientable then so is $M_1$

5 votes
2 answers
3k views

Prove that the antipodal mapping is an isometry on $S^n$. Help understanding the proof.

5 votes
1 answer
2k views

Liouville's theorem and the Wronskian

5 votes
6 answers
740 views

How to explain to a school kid that on a sphere the shortest path between 2 points is given by a great circle?

5 votes
0 answers
156 views

Abelian instantons for generic metric

4 votes
0 answers
380 views

When are two line bundles isomorphic?

4 votes
3 answers
401 views

What is the quotient space $\mathbb{C}[x,y,z]/(x^2+y^2)$?

4 votes
6 answers
2k views

3 points lie in the same straight line. Then why is this formula valid?

4 votes
4 answers
3k views

Circle to circle homotopic to the constant map?

3 votes
1 answer
418 views

Levi-Civita help

3 votes
0 answers
697 views

What exactly is a conifold for mathematicians?

3 votes
1 answer
237 views

What information can I immediately extract from a Dynkin diagram?

3 votes
1 answer
96 views

CY 3-folds are $T^2 \times \mathbb{R}$ fibrations over the base $\mathbb{R}^3$. What does it mean?

3 votes
2 answers
523 views

What exactly does the Hilbert scheme of points parametrize?

3 votes
0 answers
87 views

Can I split this integral to a sum over three contours?

3 votes
1 answer
497 views

Is the group of symplectomorphisms of a symplectic manifold the symplectic group?

3 votes
1 answer
234 views

Why do we need the $S \otimes L^{1/2}$ bundle product to determine a $Spin_c$ structure?

3 votes
1 answer
373 views

Exact sequence for the Spin group

3 votes
1 answer
666 views

What information does a group extension Ext$^1(X,Y)$ convey?

3 votes
0 answers
134 views

Natural line bundle over $\mathbb{P}^n$

3 votes
1 answer
684 views

Euler characteristic of a pair of sheaves $(E,F)$?

3 votes
1 answer
610 views

Confusion: line bundles over $\mathbb{P}^1$ and sheaves

2 votes
0 answers
83 views

How to write this product function in a compact way?

2 votes
0 answers
109 views

Log Sum Exp trick confusion with probability distributions