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1
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0answers
73 views

How many real-analytic forms exist on a real-analytic manifold?

I hope my question isn't too vague: Let $M$ be a real-analytic compact manifold (say surface for simplicity). How big is $\Omega^k(M)$ (space of global real-analytic $k$-forms)? Let me explain ...
1
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0answers
14 views

Numerical test for unique continuation principle

Is there any numerical algorithm to test the unique continuation principle for the elliptic or parabolic equations? Thank you very much.
3
votes
2answers
288 views

Grothendieck topologies on $\mathbb{C}$

I would like to consider three sheaves $\mathcal{C}^0$, $\mathcal{H}$ and $\mathcal{S}$ on $\mathbb{C}$ (endowed with the euclidean topology): the first is the sheaf of continuous $\mathbb{C}$-valued ...
8
votes
4answers
386 views

Analytic continuation of the double sum $\sum_{n,m\ge0}x^ny^mt^{nm}$

Define function $f(x,y,t)$ as the analytic continuation of the series $$f(x,y,t)=\sum_{n,m\ge0}x^ny^mt^{nm}$$ This series definitely converges when all the arguments are small enough. I would like to ...
0
votes
0answers
66 views

Existence of analytic continuation of $f(z)=\sum{n^{\alpha}} z^n$ for fractional $\alpha$

The power series $f(z)=\sum_{n \ge1}{n^{\alpha}} \cdot z^n$ has radius of convergence 1. For $\alpha \in \mathbb{N}$ it is easy to see that $f$ permits an analytic continuation to $\mathbb{C} \...
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0answers
46 views

On sequences of rational functions [duplicate]

Let $\{f_n\}_{n=0}^\infty$ be a sequence of rational functions of the following form: $$ f_n(z) = \sum_{m=1}^\infty \frac{C_{m,n}}{z-m}$$ with $C_{m,n} \in \mathbb{Z}$, $C_{1,n} = 1$, and for each $n \...
1
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0answers
70 views

Analytic continuation of an integral

Let $$f(y)=\frac{y_1^{1/3}y_2^{1/3}}{y_1+y_2+1}$$. Consider the following integral: $$F(s_1,s_2)=\int_{\mathbb{R}_+^2}f(y)^{s_1}f(y^{-1})^{s_2}\frac{dy_1dy_2}{y_1y_2}$$ where $y^{-1}=(y_1^{-1},y_2^{-...
11
votes
1answer
403 views

Distribution of zeroes of lacunary functions

In a recent Math Stack Exchange question I asked about the function $$f(z)=\sum_{n=0}^\infty z^{2^n},$$ and was informed of its status is a canonical example of a lacunary series with natural boundary ...
5
votes
2answers
233 views

Simultaneous analytic continuation of Dirichlet eigenfunctions

Let $D\subset\mathbb{R}^d$ be a bounded domain which is regular for the Dirichlet problem. There is then a complete set of orthonormal eigenfunctions $\phi_j$ with corresponding eigenvalues $0<\...
3
votes
2answers
525 views

Good book on analytic continuation?

This is a cross-post from MSE. For my Bachelor's thesis, I am investigating divergent series summation methods. One of those is analytic continuation. There are quite a few books on complex analysis ...
4
votes
2answers
511 views

I don't understand behavior of this integral, help!

In an answer to a question I needed the following integral: $$ f(z):=\int\limits_0^\infty t\coth(zt)e^{-t^2}dt; $$ it represented deviation from modularity of some other function. However I noticed ...
4
votes
1answer
333 views

Analytic continuation of a multiple contour integral

Let $W(t_1,\dotsc,t_n)$ a holomorphic function on some connected open set $U$ of $\mathbb C^n$. Let $\mathbf t^{(0)}$ a point of $U$. Assume that there exists a cycle $\gamma$ in $\mathbb C^m$ and a ...
1
vote
2answers
176 views

Analytic continuation for PI(1+z^(4^n))

How to do analytic continuation for following function? $$f(z) = \prod_{n=0}^{+\infty} {(1+z^{4^n})}$$ Evidently it satisfies $f(z)f(z^2)=\dfrac{1}{1-z}$...
5
votes
1answer
154 views

Ubiquity/scarcity of non-analytically continuable functions

Suppose f(z) is a power series with positive integer coefficients centered at zero and positive radius of convergence. What is the likelihood that f has a dense set of singularities on its circle of ...
0
votes
0answers
244 views

Analytical continuation of the reciprocal of the Zeta function

Is the reciprocal of the Zeta function analytically continuable? As $1/\zeta(n) = \sum_{n=1}^\infty \mu(n)/{n^s}$, this does not look obvious.
0
votes
1answer
227 views

Non-analyticity of convolution

I have posted a similar question in the past but let me make a final try in a simpler framework. Let $g \in C_0 ^\infty (\mathbb{R})$ be smooth and compactly supported. Define $$ f(x) = \int \big ((...
1
vote
1answer
390 views

Functional equation of the alternating zeta function

Can one let me know about the functional equation of the alternating zeta function similar to the well known for the rieman function.
1
vote
1answer
457 views

continuation of the “n-th derivative” function [closed]

let $D_{\mathbb N}$ be the standard "n-th derivative" function is it possible to make a continuation of $D_{\mathbb N}$ to non integer values? i mean a function $D_{\mathbb R}$ such that $D_{\mathbb ...
1
vote
2answers
1k views

Does a bounded real function have an analytic continuation [closed]

Consider the function $f:[0,1]\rightarrow\mathbb{R}$, where $f$ is real-analytic on the open interval $(0,1)$ $f$ is bounded on the closed interval $[0,1]$ (ie. there is some constant $C$ such that $...
3
votes
1answer
299 views

Uniqueness of analytic continuation on a domain of C^n.

Hi. I have been struggling with this question for a while now. Given a domain $\Omega \subset \mathbb{C}^n$, $\Omega^\prime = \Omega \cap \mathbb{R}^n$, and an analytic function $f: \Omega \...
0
votes
1answer
425 views

Analytical continuation of a Dirichlet series with periodic coefficients

Fix a complex number s and a real number x, does there exist an analytic continuation of the Dirichlet series $L(s,x):=\sum_{k=1}^{\infty}\frac{\sin^2(2\pi k x)}{k^s}$ to the whole complex plane ...
8
votes
3answers
763 views

analytic continuations

Analytic/meromorphic continuation is a difficult problem in general. For "motivic L-functions", the idea of proving their analytic continuations by first proving their modularity goes back, I guess, ...