All Questions
3,561 questions
-1
votes
1
answer
512
views
Does $\int_{2}^{\infty} (\pi(x)-Li(x))x^{-s-1} \mathrm{d}x$ converge on the real axis for $s>1/2$? [closed]
Consider the prime zeta function, defined for $\Re(s)>1$, by the infinite series
$$\sum_{p} p^{-s} = \sum_{m=1}^{\infty}\frac{\mu(m)}{m}\log \zeta(ms)$$ where $p$ denotes a prime, $\mu$ the Mobius ...
user146617
2
votes
0
answers
166
views
Two generalizations of the Verblunsky Theorem
I learned from this paper about the Verblunsky theorem.
My question is that: What kind of generalizations of this theorem is availlable?
In particular I am interested in the following two possible ...
- 366
2
votes
1
answer
207
views
Does this function have a holomorphic continuation in $\sigma > \frac{1}{2}$?
Define
\begin{equation}
F(\sigma) = \Re \sum_{h=1}^{\infty} \sum_{n=1}^{\infty} \frac{b_{n, h}}{n^{2\sigma}}(1+h/n)^{-\sigma}\Bigg( \frac{e^{i\log(1+h/n)}-1}{i\log(1+h/n)} \Bigg)
\end{equation} where $...
- 1,019
4
votes
0
answers
294
views
Holomorphic covers pulling back the volume form to any integer multiple
Let $M$ be a closed connected complex manifold with $\mathrm{dim}\:M=n$. Can there exist holomorphic covering maps $\phi_k:M\to M$ for all integers $k\geq 1$ such that $\phi_k^*:H^n(M, \mathbb{Z})\to ...
user145520
21
votes
7
answers
2k
views
Pros and cons of math teaching using smartboards
Currently, there is some talk in my university concerning a change in our lecture rooms from blackboards to smartboards (or other alternatives, such as a smart podium). For that reason, I'm interested ...
5
votes
1
answer
767
views
Reference for Lindelöf Hypothesis implying finitely many zeros off critical line?
Can anyone give me a reference for the following theorem on the Riemann zeta function?
If the Lindelöf Hypothesis is true (that is $\zeta(\sigma+it)=O(t^\epsilon)$ as $t\rightarrow\infty$), then ...
- 195
-3
votes
1
answer
208
views
Conformal map from a 7-sided polyhedron to a square pyramid
I have a right-angled square pyramid, $A$, whose height and base-length are $l$. By 'right-angled', I mean that the apex of $A$ lies vertically above one of the vertices in its base. Now supposed I ...
- 167
1
vote
1
answer
243
views
Subharmonic function in unbounded regions
The harmonic majorization for a subharmonic function $h$ is well-known for bounded regions $\Omega \subset \mathbb{C}$:
$$h \le 0 \text{ in }\partial \Omega \Longrightarrow h \le 0 \text{ in }\Omega.$$...
- 285
4
votes
1
answer
195
views
Pseudo-holomorphic disk which is constant along boundary
Let $(M,J,\omega)$ be a symplectic manifold with a compatible almost complex structure, $D$ be the closed unit disk in $\mathbb{C}$, and $u:(D,i)\to (M,J)$ be a $(J,i)$-holomorphic map.
Question: ...
- 357
8
votes
3
answers
1k
views
Can the topological algebra of analytic functions be endowed with a norm that defines the natural topology?
Right, so in my research in complex analysis I was puzzled by this question which may have a simple approachable answer that eludes me, but I am truly itching to find out and in need of it so I am ...
- 221
2
votes
1
answer
350
views
Poles of equivariant meromorphic functions on Riemann surfaces
Let $p:\Sigma\to \mathbb{P}^1$ be the cyclic cover of $\mathbb{P}^1$ with Galois group $\Gamma$. Let $\Gamma\cdot p$ be a free $\Gamma$-orbit on $\Sigma$. Given any character $\chi$ of $\Gamma$, does ...
- 1,457
2
votes
1
answer
454
views
Does $\sum_{n=1}^\infty \frac{\mu(n)}{n^s}$ converge for $\sigma > \frac{1}{2}$?
Looking at @Lucia's answer to this question it appears $\sum_{n=1}^\infty \frac{\mu(n)}{n^s}$ converges for $\sigma > \frac{1}{2}$. Can someone point me to a proof or provide proof for this? If I ...
- 203
3
votes
0
answers
149
views
How to enumerate branched covers of $\mathbb{P}^1$ branched over $0,1$ and $\infty$?
Setup: Let $u:\Sigma \to X$ be a holomorphic map of closed Riemann surfaces with branch points $P \subset X$. For each branch point $p \in P$, we have a partition $\Gamma_p$ of $\text{deg}(u)$ given ...
- 1,231
19
votes
9
answers
5k
views
Mathematics and autodidactism
Mathematics is not typically considered (by mathematicians) to be a solo sport; on the contrary, some amount of mathematical interaction with others is often deemed crucial. Courses are the student's ...
1
vote
0
answers
201
views
Is there a natural topology on $\mathbb{C}(t)[x_1,\ldots, x_n]$ with this property?
Is there a good topology on $A=\mathbb{C}(t)[x_1,\ldots, x_n]$ so that $A$ is a topological algebra with the following property:
For any $N>0$ and a polynomial $F\in\mathbb{C}[x_1,\ldots, x_n]$ ...
- 291
3
votes
2
answers
280
views
Reference request for the integral representation of the Hadamard product of two infinite series
Define $F(x) = \sum_{n\geq 1} f_{n}x^n$ and $G(x) = \sum_{n\geq 1} g_{n}x^n$. Then the Hadamard product of $F$ and $G$ is
$$H(x):=(F*G)(x) = \sum_{n\geq 1} f_{n}g_{n}x^n.$$
The author of Riesz ...
- 43
1
vote
1
answer
303
views
Cauchy's Integral with quadratic exponential term
As I was studying the Cauchy's integral formula, I tried to do the integral:
\begin{equation}
I = \int\limits_{-\infty}^{\infty} \frac{1}{x - a} e^{(i A x^2 + i B x)} dx
\end{equation}
with $A>0, ...
16
votes
6
answers
3k
views
How to mentor an exceptional high school student?
I have a unique and, quite truthfully, humbling opportunity. The parents of an exceptionally talented high school freshman have reached out to me and asked if I might be able to help.
This kid is ...
0
votes
4
answers
716
views
On the real part of the Riemann zeta function inside the critical strip
Denote by $\zeta$ the Riemann zeta function. Does $\Re\zeta(s)$ ever vanish for $\frac{1}{2}<\Re(s)\leq 1$ ?
- 1,019
17
votes
4
answers
10k
views
Analytic implicit function theorem
I'm looking for a proof of the analytic implicit function theorem (IFT). The only related proof I could find was the holomorphic inverse function theorem (by Henri Cartan). On Wikipedia, the analytic ...
- 183
4
votes
1
answer
344
views
Asymptotic analysis using the p-adic Mellin Transform?
In ordinary analysis, given a sufficiently nice $f:\left[0,\infty\right)\rightarrow\mathbb{C}$, if we can compute the Mellin transform: $$\mathscr{M}\left\{ f\right\} \left(s\right)=\int_{0}^{\infty}x^...
- 1,284
30
votes
4
answers
3k
views
Distribution of roots of complex polynomials
I generated random quadratic and cubic polynomials with coefficients in $\mathbb{C}$
uniformly distributed in the unit disk $|z| \le 1$. The distribution of the roots of 10000
of these polynomials are ...
- 151k
2
votes
0
answers
89
views
A weighted mean of roots of unity
In my research, I have come across the following problem:
Let $n \in \mathbb{N}$ and $r \geq 0$ be given. For $\theta \in [0,2 \pi)$, define
$$f(\theta) = \biggl| \frac{\sum_{j=0}^{n-1} e^{2 \pi ij/n} ...
- 121
28
votes
2
answers
1k
views
Are there irreducible polynomials with all zeros on two concentric circles?
This is somewhat similar to this recent question, but extending in a different direction.
Let $f(x)$ be an irreducible polynomial of degree $n$ with integer coefficients. Call such $f$ a bicycle ...
- 13.4k
2
votes
1
answer
163
views
Theta series analogues for higher degree forms
It is simple to see that the following series converges absolutely and uniformly on $\mathcal{H}$ for all k positive:
$F_{2k}(z) = \sum_{n \in \mathbb{Z}} q^{n^{2k}}$
And this series being a ...
- 73
11
votes
5
answers
4k
views
Applications of Liouville's theorem
I'm looking for "nice" applications of Liouville's theorem (every bounded entire map is constant) outside the area of complex analysis.
An example of what I'm not looking for : a non-constant entire ...
6
votes
1
answer
527
views
Holomorphic extensions of a non-vanishing real-analytic function
Let f(z) be a holomorphic function defined on an open neighborhood $R$
of the interval $I=[0,1]\subset \mathbb{R}$. Assume $f$
does not vanish on $I$. Then $g(x) = |f(x)|$ is a real-analytic
function ...
- 20.2k
2
votes
0
answers
203
views
Derivative of a polynomial $P(z)$ and the derivative of the conjugate reciprocal of $P(z)$
Let $P(z)=\sum_{n=0}^na_nz^n$ be a polynomial of degree $n$ having no zeros in $|z|<1.$ Let $Q(z)=z^n\overline{P(1/\overline{z})}.$ Then it is an easy exercise to show that $\Re\left(zP'(z)/P(z)\...
- 559
8
votes
0
answers
315
views
Singularities of a morphism from a smooth projective variety to an abelian variety
Let $f: X\to A$ be a (flat) morphism from a smooth complex projective variety $X$ to an abelian variety $A$. Consider the following natural diagram:
$$T^*X\overset{df}{\longleftarrow}X\times H^0(A, \...
- 1,081
15
votes
1
answer
758
views
Teaching cohomology via everyday examples
This question is a "sequel" to my similar questions about the fundamental group and homology. All of these questions were inspired by seeing a talk, by Tadashi Tokieda, about the interesting physics ...
28
votes
2
answers
2k
views
A 14th and 26th-power Dedekind eta function identity?
Given the Dedekind eta function $\eta(\tau)$. Define $m = (p-1)/2$ and a $24$th root of unity $\zeta = e^{2\pi i/24}$.
Let p be a prime of form $p = 12v+5$. Then for $n = 2,4,8,14$:
$$\sum_{k=0}^{p-...
- 12.6k
2
votes
1
answer
125
views
Twisted winding number
Consider the contour integral
$\frac{1}{2\pi i}\oint_\gamma\chi(z)\frac{dz}{z}\,,$
where $\gamma$ is a (not necessarily simple) closed curve lying in $\mathbb{C}\setminus{0}$ and $\chi\colon\mathbb{...
- 1,453
1
vote
0
answers
196
views
Is a mixture of real analytic functions again analytic?
Let $$h : \mathbb{R}^2 \to \mathbb{R}^+.$$
Suppose that for each $x$, $h(x, y)$ is a real analytic function of $y$.
Let $\mu(dx)$ be a finite measure on $\mathbb{R}$, and for each $y$, suppose that
$$...
- 103
3
votes
0
answers
68
views
Analogue of Carlson's theorem for poles in the upperhalf plane?
Let $f:\mathbb{H}\to \mathbb{C}$ be a holomorphic function on the upper half plane. Even it is not defined on the real line, we will define $\mathrm{ord}_{z=z_0}f(z)$ to be the unique value $\xi\in\...
- 2,902
1
vote
0
answers
161
views
Justify $\int_0^\infty e^{-ax^2}\ \mathrm{d}x$ for complex $a$ and zero real part [closed]
(Reposted from math stack exchange)
I have searched and failed to find a rigorous proof showing that
$$\int_{0}^\infty e^{-ax^2}\ \mathrm{d}x = \frac{\sqrt{\pi}}{2\sqrt{a}}$$
is true for $\Re(a)=0$ ...
user161698
6
votes
1
answer
324
views
Almost complex manifold of dimension 2... locally isomorphic to ℂ?
I know that this is supposed to be standard, but I don't know how to search for it... hence the question:
Let $J$ be an almost complex structure on $M:=\mathbb R^2$, i.e., a $C^\infty$ section of $\...
- 43.2k
1
vote
0
answers
155
views
Can the Selberg-Delange method be extended to analyzing $\sum_{n<x}\frac{a_n}{n}$?
The famous Selberg-Delange method takes sequences $a_n$ whose associated DGF $F(s)=\sum_{n=1}^{\infty}\frac{a_n}{n^s}$ has a representation
$$F(s)=G(s;z)\zeta^z(s)$$
where $G(s;z)$ is "nice ...
- 2,902
0
votes
1
answer
325
views
Injectivity of analytic functions
Suppose $f : \mathbb{R} \rightarrow \mathbb{R}^n$ is a real analytic function on $(a, \infty)$. I have two questions:
Suppose $||f(x)|| \rightarrow \infty$ as $x \rightarrow \infty$. I know without ...
- 431
19
votes
2
answers
960
views
Zeros of MacLaurin polynomials for the exponential function
Asked but never answered at MSE.
Let $\exp_n(z)$ denote the nth degree Taylor polynomial of $e^z$ :
$\exp_n(z) = 1 + z + z^2/2! + ... + z^n/n! \;$ .
The zeros of $\exp_n(z)$ were studied by ...
- 1,411
2
votes
2
answers
436
views
Coefficients of entire functions with specified zero set
Let $Z \subseteq \mathbb{C}$ without limit point. By the Weierstrass factorization theorem there is an entire function $h$ those zero set is $Z$. Let $a_n > 0$ be a sequence where $\lim_n \sqrt[n]{...
- 2,160
2
votes
1
answer
275
views
Binomial transform of Dirichlet series
Let $\Theta(s)$ be a Dirichlet series , and let $\beta$ be its abscissa of convergence:
$$\Theta(s)=\sum_{n=1}^{\infty}\frac{\theta(n)}{n^{s}}\;\;\;\;\;\;\Re(s)>\beta$$
And let $\left\{a_{n}\right\}...
- 181
2
votes
1
answer
192
views
Existence of a distinguished continuous version of the logarithm of a continuous function
Let $E$ be a $\mathbb R$-Banach space and $\varphi\in C^0(E,\mathbb C\setminus\{0\})$ with $\varphi(0)=1$.
I want to show that there is an unique $\psi\in C^0(E,\mathbb C)$ with $\psi(0)=0$ and $$\...
- 167
3
votes
1
answer
144
views
Coefficient problem in the class $\Sigma$
Let $\Sigma$ be the class of univalent (injective) holomorphic functions on $\mathbb{C}\backslash \mathbb{D}$ where $\mathbb{D}$ is the closed unit disk. Analogous to the famous Bieberbach conjecture ...
- 133
2
votes
0
answers
65
views
On a question relating integral equation:
I don't know if the following question qualifies as research level. If it isn't, sorry.
Set the following terminology:
$ \alpha_1 =\alpha_1(t,x)=t(\tan^{-1}(x)+c)$
$\alpha_2=\alpha_2(s,x)=s(\tan^{-1}(...
- 41
1
vote
1
answer
186
views
Existence of entire function that yields periodicity
I have the following question:
Does there exist an entire function $f(z)$ where $z=x+iy$ such that
$$g(x,y) =e^{-2\pi y^2}f(z)$$
is periodic in both $x$ and $y$ direction, i.e. $$\forall x,y: g(1,y)=g(...
- 124
1
vote
1
answer
182
views
Analyze a function defined in terms of an integral
Here is a question that really has puzzled me for quite a while. I happened to see this function defined in terms of an integral
$$f(x):=\int_0^{\pi/2}\frac{2e^{x+e^x\cos y}}{1+\left(e^{e^x\cos y}\...
- 1,350
3
votes
0
answers
132
views
Clarifications about a proof of (the measurable Riemann) mapping theorem in Hubbard's book on Teichmuller theory,
On page 151 of Hubbard's book, the author is proving the following theorem( Prop.4.6.2 ):
Suppose $\mu$ is a real analytic function on a domain $U$ of $\mathbb{C}$. Then every $z \in U$ has a ...
- 41
7
votes
3
answers
3k
views
Problems reducing to a graph-theory algorithm
This is essentially a question in pedagogy -- the answers could be useful to teach (or rather, motivate) graph theory, and especially the algorithmic side of it.
I have been very impressed with this ...
- 2,287
0
votes
1
answer
753
views
Real part of entire function property
Is there any characterization of the set of entire functions $f(z) $ such that $\Re(f(z)) \geq \Re(\overline{f(\bar{z})})$ for all $z\in \mathbb{C}^{+} $?
($\Re$ stands for the real part)
Edit: I ...
- 39
2
votes
3
answers
5k
views
Specializing in Complex Analysis [closed]
May someone kindly provide a useful list of books on complex analysis that would be appropriate for a graduate student intending to specialize in that area.