James C's user avatar
James C's user avatar
James C's user avatar
James C
  • Member for 9 years, 3 months
  • Last seen more than a week ago
7 votes
1 answer
486 views

$\pi: E \rightarrow M$ ($E$ is a vector bundle) admits a global frame iff $E$ is a trivial vector bundle over $M$.

5 votes
1 answer
729 views

The existence of a local orthonormal frame

4 votes
1 answer
151 views

If two vectors are orthogonal, then is their covariant derivative 0?

4 votes
1 answer
282 views

Is there an intuitive way to understand why $\det(AB)=\det(A)\det(B)\;$?

4 votes
1 answer
196 views

Use of choice function in Urysohn's lemma?

4 votes
1 answer
333 views

Is there a reason that test functions are chosen to have a compact support?

3 votes
3 answers
124 views

Let $a_n$ be a sequence of nonnegative numbers such that $a_n \rightarrow b$. Then, $\lim_{n \rightarrow \infty} \frac{(a_{n+1})^{n+1}}{(a_n)^n}$ =?

3 votes
1 answer
56 views

Is $x \mapsto (x, |x|)$ locally diffeomorphic to $\mathbb R$ at $x = 0$? (there is a philosophical question)

3 votes
2 answers
149 views

If $y = x^2$, then what is $dy$? (What's the definition of differential?)

3 votes
1 answer
55 views

$\frac{d}{ds} \langle T, T \rangle = 2\langle \nabla_S T, T \rangle$?

3 votes
1 answer
193 views

Is it always true that intersection of two Sylow p-subgroups is trivial?

3 votes
1 answer
192 views

Am I allowed to have an irrational distance for a rational metric space?

3 votes
1 answer
75 views

Integration of $\int_{\mathbb{R}} e^{-\pi(x+i\xi)^2} dx$?

2 votes
1 answer
486 views

How can I construct a homotopy between a constant function to a continuous function?

2 votes
4 answers
278 views

Question about logical implication $P\to Q$ [duplicate]

2 votes
1 answer
246 views

How can I express $3 \cdot 7 \cdot 11 \cdots (4n+3)$ in terms of factorial?

2 votes
1 answer
21 views

If $R$ is an integral domain without $1_R$ and $a=b$, then $ac \neq b$ for every $c$?

2 votes
3 answers
1k views

Fourier Transformation in exponential form negative infinity

2 votes
0 answers
24 views

Does unit ball in homogeneous Riemannian manifold $M$ translates isometrically to another unit ball in $M$?

2 votes
1 answer
125 views

Is the notion of cardinal number used in analysis?

2 votes
0 answers
478 views

Properties of Unit Tangent Bundle

2 votes
1 answer
387 views

Any counter-example of pasting lemma?

2 votes
5 answers
112 views

Use Implicit Differentiation to find $\frac{d^2y}{dx^2}$?

2 votes
0 answers
40 views

Riesz-Fischer in $L^\infty$ clarification needed.

2 votes
1 answer
50 views

If $T \in L(\mathbb R^2)$ with $T^3 = I$, then is $T$ an isometry?

2 votes
0 answers
63 views

Is it possible to construct a vector field on a manifold from a curve [duplicate]

2 votes
0 answers
105 views

closed set with unique distance minimizing element is convex?

1 vote
0 answers
54 views

preimage of $[0,1]$ of matrix norm $\| \cdot \|_{n,m}: \mathbb R^{m,n} \rightarrow \mathbb R$ is compact. [duplicate]

1 vote
0 answers
123 views

Is there an intuitive reason why variance of exponential distribution is $\frac{1}{\lambda^2}$?

1 vote
0 answers
54 views

What is $\partial_t g^{ij}(t)$? [duplicate]