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Paul Siegel
  • Member for 11 years, 10 months
  • Last seen more than a week ago
44 votes
2 answers
856 views

Is there a naive proof that $x - \frac{x^3}{3!} + \frac{x^5}{5!} - \ldots$ has period $2\pi$?

41 votes
2 answers
2k views

Which polynomials are characteristic polynomials of a symmetric matrix?

32 votes
1 answer
3k views

When is $C_0(X)$ separable?

14 votes
1 answer
1k views

Coordinate free proof that curvature is the "square" of the connection

12 votes
1 answer
2k views

Elementary applications of Krein-Milman

10 votes
0 answers
1k views

Mayer-Vietoris implies Excision

9 votes
1 answer
1k views

Is the space of uniformly left continuous functions on [0,1] complete?

8 votes
2 answers
2k views

Modulus of Continuity

8 votes
1 answer
1k views

An isomorphism in relative De Rham cohomology

7 votes
0 answers
132 views

Products in $C^*$-algebra $K$-theory

7 votes
2 answers
988 views

Modulus of Continuity, Take 2

7 votes
1 answer
383 views

Is there a statistical interpretation of Green's theorem, Stokes' theorem, or the divergence theorem?

7 votes
5 answers
567 views

Complete and elementary proof that $(a^x - 1)/x $ converges as x goes to 0

6 votes
3 answers
1k views

A question related to Buffon's needle

6 votes
1 answer
215 views

Effect of permuting coordinates on K-theory

6 votes
3 answers
792 views

Can closed curves have small curvature?

5 votes
1 answer
213 views

Operator K-theory and the unitary group

5 votes
2 answers
1k views

"Abstract nonsense" proof that the fundamental group of a topological group is abelian

5 votes
2 answers
833 views

Are all critical points of energy geodesics?

5 votes
1 answer
423 views

Is there such a thing as "cartesian closure" in category theory?

4 votes
1 answer
716 views

Maurer-Cartan 1- form as a connection 1-form

4 votes
1 answer
1k views

The (distributional) Fourier transform of the unit step function

4 votes
2 answers
417 views

Yet another complex analysis problem

4 votes
3 answers
603 views

An ignorant question about the incompleteness theorem

3 votes
1 answer
481 views

How do you prove that every curve of constant width is convex?

3 votes
0 answers
244 views

The magnetic monopole and the Hopf bundle

3 votes
3 answers
271 views

More elementary proof that $\pi_n(S^n) \cong \mathbb{Z}$

3 votes
1 answer
235 views

Is a graph determined up to isomorphism by its path category?

2 votes
1 answer
76 views

Is a graph uniquely determined by its weighted 2-step graph?

2 votes
2 answers
451 views

A silly question about $C_0$