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Description of all biholomorphic maps from annulus [duplicate]

Consider the collection $\mathcal{C}$ of all maps $f \colon B_1 -\overline{B}_\beta \to \mathbb{C}$ such that $f$ is biholomorphic onto its image. Is this collection $\mathcal{C}$ path-connected? In ...
Jinyang wu's user avatar
3 votes
2 answers
116 views

Vector bundles over a Stein space are projective

It is a "well known" fact that locally free sheaves over a Stein space $X$ are projective as $\mathcal{O}_X$-modules (see e.g. just after Lemma 1.6 in O'Brian-Toledo-Tong's "The trace ...
Tim's user avatar
  • 1,109
-3 votes
1 answer
193 views

Bounding a number-theoretic integral

Find a good upper bound on $$\int_1^T\frac{\zeta'(s)}{\zeta(s)\zeta(1-s)}X^sdt,$$ where $s=c+it$ for a constant $c>1$ and $X>0$ is a parameter. If needed, we can assume RH. My attempt here is ...
charlie_beck's user avatar
0 votes
1 answer
118 views

Nonstationary phase method for oscillatory integral

I want to approximate an integral of the form $$\int_a^bf(t)e^{ig(t)}dt,$$where $f(t)$ is smooth, $g(t)$ is real-valued and smooth. The stationary phase method says that if $t_0\in [a,b]$ is such that ...
charlie_beck's user avatar
2 votes
0 answers
37 views

Theta series of well-rounded lattices

I've started looking into well-rounded Euclidean lattices and I was interested in learning whether their theta series have any interesting properties, but haven't found much in terms of bibliography ...
JBuck's user avatar
  • 223
3 votes
1 answer
326 views

Holomorphic homotopy conjecture

Let $X$ be a smooth projective variety over the complex numbers, and let $\text{Coh}(X)$ be the category of coherent sheaves on $X$. Consider the dg-category $\text{Perf}(X)$ of perfect complexes on $...
Nhan Le's user avatar
  • 31
2 votes
2 answers
361 views

Size of $\zeta'(s)$ at its zeros

How large can the derivative of the Riemann zeta function be at its zeros? More specifically, let $\rho$ be a zero of the zeta function with $\Im(\rho)\in (0,T]$. What can we say about $|\zeta'(\rho)|...
user avatar
3 votes
1 answer
178 views

Analytic continuation to the Mittag-Leffler star using Mittag-Leffler summation

This is a reference request for a theorem I thought I had read in a book by Steven Krantz, but I can no longer find it. Searching for Mittag-Leffler star, I can find references to the following result....
Greg Zitelli's user avatar
  • 1,084
1 vote
1 answer
64 views

Reference dual Dirichlet space $D^1$

Let $\mathbb{D} = \{ z \in \mathbb{C} : |z| < 1 \}$ be the unit disk. The Bergman space $A^1 = A^1(\mathbb{D})$ is the Banach space of holomorphic functions on $\mathbb{D}$ such that $$ \|f\|_{A^1} ...
Scottish Questions's user avatar
4 votes
0 answers
168 views

Explicit bounds on gaps between zeros of $\zeta^\prime(s)$

In $\S$9.1 of "Theory of the Riemann Zeta Function", Titchmarsh uses Borel-Carathéodory and Hadamard Three Circles to show that every circle of radius 6 and center $3+iT$ contains a zeros of ...
Stopple's user avatar
  • 11.1k
1 vote
1 answer
151 views

SOT and WOT convergence of Toeplitz operators

For the Hardy space $H^2$, every $\phi \in L^\infty (\mathbb T)$ induces a bounded Toeplitz operator $T_\phi$ on the Hardy space and $\lVert T_\phi \rVert = \lVert \phi \rVert _{\infty}$. Consequently,...
ash's user avatar
  • 151
-1 votes
1 answer
84 views

Reference Request: Continuous extension of conformal maps

currently I am trying to find some references on the continuous extension of conformal maps between two simply connected domains of the Riemann sphere $\hat{\mathbb C}$. Let $\gamma_1,\gamma_2$ be two ...
A.s. graduate student's user avatar
5 votes
1 answer
172 views

Properties of Poisson Integral and Traces of functions in Sobolev space $W^{1,2} (\mathbb D)$

Let $W^{1,2}(\mathbb D)$ be the complex valued Sobolev space on $\mathbb D$ where $\mathbb D $ is the open unit disk of the complex plane. By definition, $W^{1,2} (\mathbb D)$ is the set of all ...
ash's user avatar
  • 151
3 votes
0 answers
219 views

Schwartz's theorem without English language reference

I'm reading the paper "Spectral Synthesis And The Pompeiu Problem" by Leon Brown, Bertram M. Schreiber and B. Alan Taylor, Annales de l’Institut Fourier 23, No. 3, 125-154 (1973), MR352492, ...
Holden Lyu's user avatar
3 votes
1 answer
249 views

Is Toeplitz operator on the Bergman space bounded iff its symbol is bounded?

It is fairly well known that if $T_\varphi$ is a Toeplitz operator on the Hardy-Hilbert space, then $\lVert T_\varphi \rVert = \lVert \varphi \rVert _{\infty}$. Now, if $\varphi \in L^\infty (\mathbb ...
ash's user avatar
  • 151
6 votes
1 answer
290 views

Analytic maps on Banach spaces: analyticity upgrade

Consider the following problem. Let $E,F,G$ be real or complex Banach spaces, such that $F\subset G$ with continuous embedding. Let $U\subset E$ an open set and $$ f:U\to G $$ an analytic map, such ...
Lorenzo Pompili's user avatar
6 votes
0 answers
200 views

Reference request: Automorphisms of $\mathbb C\{x,y\}$ which preserve the equation of the cusp, $x^3 - y^2$

In my research I encountered automorphisms of the ring of convergent power series $$\varphi: \mathbb C\{x,y\} \to \mathbb C\{x,y\},$$ which preserve $f = x^3 - y^2$, i.e. $\varphi(f) = f$. I'm ...
red_trumpet's user avatar
  • 1,286
3 votes
1 answer
458 views

Limit of an infinite series with quadratic arguments

I have encountered a limiting process on some infinite series. So, I would like to ask: QUESTION. Assume $n$ is an even positive integer. Is this true? $$\lim_{r\rightarrow1^{-}}\sum_{j=1}^{\infty}\...
T. Amdeberhan's user avatar
0 votes
0 answers
109 views

Affine scheme over ring of meromorphic functions with finite poles on unit circle

I am looking into the set $S$ of meromorphic functions with a finite number of poles on the unit circle (i.e., rational functions with poles on the unit circle). I assume that any $h\in S$ has the ...
Jens Fischer's user avatar
3 votes
0 answers
89 views

Transformation of Julia set sequence emerging from meromorphic function

I consider a sequence of meromorphic functions on the Riemann sphere $f_k:\hat{\mathbb{C}} \to \hat{\mathbb{C}}$ for $k\in\mathbb{N}$ of the form $$f_k(z)=\sum_{j=1}^{n_k}\dfrac{1}{(z-p_j)^{c_j}}$$ ...
Jens Fischer's user avatar
7 votes
1 answer
488 views

On a paper by Dimitrie Pompéiu and on one (in two parts) by Edmund Landau

To celebrate the new year and the future of mathematics (or the mathematics of future), I see no better way to ask a question stemming from my researches on power series. The two papers the title ...
Daniele Tampieri's user avatar
4 votes
2 answers
373 views

Abel–Plana formula with fractional offset

The Abel–Plana formula compares the sum $\sum_{n=0}^\infty f(n)$ to the integral $\int_0^\infty f(x)\,dx$, \begin{equation} \sum_{n=0}^{\infty}f\left(n\right)-\int_{0}^{\infty}f\left(x\right)dx=\frac{...
Carlo Beenakker's user avatar
5 votes
0 answers
321 views

Approximating $\zeta^{(r)}(s)$ by a sum

Let $\eta:[0,\infty)\to [0,\infty)$ be compactly supported, continuous and piecewise $C^1$, with its derivative $\eta'$ being of bounded variation. It is completely unsurprising that one can prove (...
H A Helfgott's user avatar
  • 20.1k
0 votes
1 answer
128 views

Rational approximation for continuous function on curve $\Gamma$

Let $\Gamma \in C^{1,\lambda}$ be an oriented Jordan curve in complex plane $\mathbb{C} $, $\mathrm{R}(\Gamma)$ the set of all rational functions without poles on $\Gamma $. "$\mathrm{R}(\Gamma)$...
Yidong Luo's user avatar
1 vote
0 answers
127 views

an eigenvalue problem for Jacobi Forms

Assume $G(q,z)$ is a Jacobi form of a certain index k. It is known that $G$ can be expanded in a Taylor series with coefficients in the ring of quasi-modular forms (generators $E_2, E_4$ and $E_6$). $\...
T. Amdeberhan's user avatar
7 votes
0 answers
218 views

Analytic continuation of Dixon's identity

Many well-known combinatorial identities has an analytic version. For example, the following identities $$ 2^n = \sum_{k=0}^n \binom{n}{k} $$ $$ \binom{2n}{n} = \sum_{k=1}^n \binom{n}{k}^2 $$ can be ...
Pluviophile's user avatar
  • 1,608
1 vote
0 answers
111 views

Residues of analytic operators

Suppose we have analytic operators $P_{z}: C^1[0,1]\to C^1[0,1]$, where $z \in \mathbb{C}$, and the spectrum of $P_{z_0}$ possesses an isolated eigenvalue $1$ (assuming multiplicity is 1 and $I-P_z$ ...
opera's user avatar
  • 11
2 votes
0 answers
90 views

Computing a complex integral with many poles

For an integer $k\geq 1$, let $f:\mathbb{C}^k\to\mathbb{C}$ be such that $f$ is analytic in the region $\text{Re}(u_i) > -1$ (say) for each $1\leq i \leq k$, and decays rapidly on vertical lines (i....
Joshua Stucky's user avatar
1 vote
2 answers
354 views

Reference request and clarification for Central Limit Theorem for complex random variables

I'm looking for a reference and a proof of the following version (or eventually a more general version) of the Central Limit Theorem for complex random variables. Theorem. Let $Z_1, Z_2, \dots, Z_n$ ...
rosan98's user avatar
  • 361
1 vote
0 answers
210 views

Proving that quotient of orthogonal polynomials is a Padé approximant of Stieltjes transform

This question is reposted from Math Stack Exchange (you can see the original post here). The motivation for reposting is that I feel like the question isn't getting much attention in MSE - if there is ...
Rodrigo's user avatar
  • 51
6 votes
3 answers
536 views

A need for analytic continuation of a finite sum function

Let $\varphi(n):=(-1)^{n+1}(n+1)2^{2n}$. I am able to prove the following identity (${\color{red}{\mathbf{LHS}}}$=infinite series, ${\color{blue}{\mathbf{RHS}}}$=finite sum) \begin{align*} {\color{red}...
T. Amdeberhan's user avatar
29 votes
2 answers
2k views

Contractibility of the space of Jordan curves

Is the space of Jordan curves in $\textbf{R}^2$ contractible? In other words, is there a canonical or continuous way to deform each Jordan curve to the unit circle $\textbf{S}^1$. If the curves are ...
Mohammad Ghomi's user avatar
4 votes
0 answers
279 views

Order of growth of $\left|\frac{1}{\zeta’(\rho)}\right|$ as $\Im(\rho)\rightarrow\infty$?

Let $\zeta$ denote the Riemann zeta function, and let $\rho\in\mathbb{C}$ be a variable that takes its values among the zeros of the zeta function, so that $\zeta(\rho)=0$, and write $\rho=\sigma+it$. ...
EGME's user avatar
  • 1,018
4 votes
1 answer
450 views

Riemann mapping theorem with smooth boundary

This is closely related to the question here. The setup is that $U\subset\mathbb{C}$ is an open bounded simply connected domain with $C^\infty$ boundary. If $\phi:U\rightarrow\mathbb{D}$ is a ...
J_P's user avatar
  • 439
12 votes
3 answers
784 views

Can the equation $1+z+z^2=z^n$ for natural $n$ have multiple complex roots $z$?

The question is stated in the title of this post. It is easy to see that, if $z$ is a multiple root of $p_n(z):=1+z+z^2-z^n$, then $(n-2)z^2+(n-1)z+n=0$, so that we can successively express $z^2,\dots,...
Iosif Pinelis's user avatar
2 votes
3 answers
478 views

Groups of conformal isomorphisms of simply connected surfaces

By the uniformization theorem every connected and simply connected surface $M$ is conformally equivalent to one of the following three surfaces: open disk $D$, complex plane $\mathbb{C}$, or $2$-...
Sergiy Maksymenko's user avatar
3 votes
1 answer
173 views

Can we define $\partial\bar{\partial}(\log|z_1|^2)\wedge \partial\bar{\partial}(\log|z_2|^2)$ as a current?

In complex analysis, by Poincare-Lelong theorem, we have $$ \frac{\sqrt{-1}}{\pi}\partial\bar{\partial}(\log|z|^2)=T_{z=0} $$ as currents, where $$ T_{z=0}(\eta)=\int_{z=0}\eta. $$ Now suppose we have ...
Zhaoting Wei's user avatar
  • 9,009
4 votes
0 answers
159 views

Correct way to extend a sequence defined on the naturals into the complex plane

Preamble Sequences $a_n$ defined on the natural numbers are clearly not uniquely interpolated by only one function. In particular, given an interpolation $f(n) = a_n$, then $f(n) + \sin(2\pi n)$ is ...
Caleb Briggs's user avatar
  • 1,730
9 votes
1 answer
657 views

Is anything known about the power series $\sum x^p$ for $p$ prime?

I'm interested in information about the power series $$\sum_{\text{$p$ prime}} x^p$$ and the related power series $$\sum_{n=1}^\infty (-1)^n x^{p(n)}$$ where $p(n)$ is the nth prime. Immediately, the ...
Caleb Briggs's user avatar
  • 1,730
5 votes
1 answer
170 views

Analytic continuation for disjoint domains

This question is a question about nomenclature more than anything. I have shown all the math, but I don't know what to search for for similar results. In such a sense, it is more so a reference ...
Richard Diagram's user avatar
2 votes
0 answers
138 views

On the solutions of $_2F_1(\alpha, \beta; \gamma, z) = \Lambda$

More General Question Let $$F(\alpha,\beta;\gamma;z) = \sum_{n=0}^{+\infty} \frac{(\alpha)_n(\beta)_n}{(\gamma)_nn!}z^n, \quad |z| < 1, \quad (x)_n = x(x+1)...(x+n-1), \quad (x)_0 = 1$$ be the ...
Desura's user avatar
  • 233
2 votes
1 answer
304 views

Is it possible to define pseudodifferential operator $p(x,T)$ using Cauchy integral formula?

I was wondering how I can define a pseudodifferential operator using Cauchy integral formula. Consider a differential operator $p(T)$ ($p$ is a polynomial for instance). $p(T)$ can be defined as: $$\...
Mirar's user avatar
  • 350
2 votes
1 answer
112 views

References for group of invariance of the Painlevé property

I'm searching for some references about groups of invariance of the Painlevé property other than the book of Robert Conte or more generally birational transformation of Riemann surfaces.
Redouane Khaled's user avatar
0 votes
1 answer
58 views

Analytic continuation of spline wavelets (reference request)

I would like to extend (cubic or higher degrees) spline wavelets to complex domain. First, does this continuation exist? Second, I appreciate it if anyone could point me to some references.
Mirar's user avatar
  • 350
7 votes
1 answer
206 views

Is the Gauss hypergeometric function $_2F_1(a,b;c,z)$ univalent in $\left|z - \frac{1}{2} \right| < \frac{1}{2}$?

Consider the Gauss hypergeometric function $$_2F_1(a,b;c,z) = \sum_{n=0}^{+\infty} \frac{(a)_n(b)_n}{(c)_nn!}z^n, \quad |z| < 1, \quad (x)_n = x(x+1)\cdots(x+n-1), \quad (x)_0 = 1$$ The Encylopedia ...
Desura's user avatar
  • 233
1 vote
0 answers
116 views

Converse of transfer theorem : does asymptotic behaviour of coefficients describe the singularity?

I'm interested in Singularity Analysis after reading this Math.Stack post. In the "Analytic Combinatorics" book by P. Flajolet and R. Sedgewick, at p.390, the following transfer theorem (...
Desura's user avatar
  • 233
3 votes
2 answers
243 views

Is every planar bounded $C^2$ domain finitely connected?

Let $\Omega \subset \mathbb R^2$ be a bounded $C^2$ domain. Is $\Omega$ then finitely connected? As I learned recently a domain in $\mathbb R^2$ is finitely connected iff “[its] complement has ...
Keba's user avatar
  • 313
0 votes
1 answer
129 views

Seeking an integral formulation for an algebraic function

While working with a generating function for the Catalan numbers, I came across the integral representation $$\frac1{1+\sqrt{1-4x}}=\frac1{2\pi}\int_0^{\infty}\frac{\sqrt{t}}{(t+\frac14)(t-x+\frac14)}\...
T. Amdeberhan's user avatar
3 votes
0 answers
184 views

"Circulant-Vandermonde" matrix: in search of a formula

An $n\times n$ circulant matrix $\mathbf{X}_n$ has the form \begin{align} \mathbf{X}_n= \begin{bmatrix} x_1 & x_2 & \cdots & x_{n-1} & x_n \\ x_2 & x_3 & \cdots & x_n&...
T. Amdeberhan's user avatar
0 votes
1 answer
163 views

Reference(s) on the smallest concave majorant for the sequence of coefficients of a given power series?

This question is based on this Math.SE answer, so let's recall a few concepts dealt with there. If $\{a_n\}_{n\in\Bbb N}$ is the sequence of coefficients of a power series $\sum_{n=0}^\infty a_nz^n$ ...
Daniele Tampieri's user avatar

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