Skip to main content

All Questions

Filter by
Sorted by
Tagged with
129 votes
2 answers
16k views

What are the shapes of rational functions?

I would like to understand and compute the shapes of rational functions, that is, holomorphic maps of the Riemann sphere to itself, or equivalently, ratios of two polynomials, up to Moebius ...
Bill Thurston's user avatar
38 votes
3 answers
8k views

The error in Petrovski and Landis' proof of the 16th Hilbert problem

What was the main error in the proof of the second part of the 16th Hilbert problem by Petrovski and Landis? Please see this related post and also the following post.. For Mathematical development ...
Ali Taghavi's user avatar
22 votes
13 answers
7k views

Is there a "crash-course" book on Abelian varieties (e.g., an introduction for physicists)?

Hello, In our (rather applied) theoretical physics research, we have encountered an important class of problems, which seem to require an understanding of Abelian functions (unfortunately, this ...
Victor Galitski's user avatar
17 votes
5 answers
2k views

Arithmetic dynamics and dynamics on moduli spaces

The following question is more of a request for pointers to suitable literature on introductory material for arithmetic dynamics and dynamics on moduli spaces. In my dissertation, I have been ...
user avatar
15 votes
8 answers
4k views

Are there some original papers or books related to applications of algebraic topology and algebraic geometry in complex dynamic systems

Recently I have much interest in algebraic topology and algebraic geometry. I am a student of the field of complex dynamical systems. According to my knowledge, my friends told me that there are many ...
14 votes
5 answers
2k views

Rational maps with all critical points fixed

What can be said about rational self-maps of $\mathbb P^1$ for which all critical points are also fixed points ? If all but one of the fixed points are critical, there is a characterization in http://...
Jorge Vitório Pereira's user avatar
11 votes
1 answer
1k views

Generating functions of Collatz iterates?

Let $C(n) = n/2$ if $n$ is even and $3n+1$ otherwise be the Collatz function. We look at the generating function $f_n(x) = \sum_{k=0}^\infty C^{(k)}(n)x^k$ of the iterates of the Collatz function. The ...
mathoverflowUser's user avatar
11 votes
1 answer
686 views

Do quantum "Sure-Shor separators" have a natural Veronese/Segre classification? (question inspired by Gil Kalai and Aram Harrow)

Aram Harrow asked: "Is there any place this is written up?" Update  Partly in answer to Aram's question, the thermodynamical properties of varietal dynamical systems now are written-up in ...
John Sidles's user avatar
  • 1,389
11 votes
0 answers
252 views

Can the orbit with respect to a rotation on the torus hit an algebraic variety infinitely often?

Question: Does there exist a $d$-tuple $\alpha = (\alpha_1,\dots,\alpha_d) \in \mathbb{R}^d$ (with $1,\alpha_1, \dots,\alpha_d$ linearly independent over $\mathbb{Q}$) and an algebraic variety $V \...
Jakub Konieczny's user avatar
10 votes
2 answers
719 views

The height of an orbit under rational self-maps

I have this basic question on which, strangely enough, the algebraic dynamics literature appears to be silent. But the question does not appear to be totally trivial or uninteresting to me - am I ...
8 votes
2 answers
684 views

Birational Automorphisms and infinite divisibility

Suppose $X$ is some algebraic variety. It can be over $\mathbb{C}$, but it doesn't have to (but char $0$ preferred). Is it possible that the additive group $\mathbb{Q}$ acts on it birationally, ...
sfilip's user avatar
  • 273
8 votes
2 answers
317 views

Dimension of orbit versus invariant functions

$\def\CC{\mathbb{C}}$Let $K = \CC(x_1, \ldots, x_n)$ and let $G$ be a countable group of automorphisms of $K$; in the cases I care about, $G \cong \mathbb{Z}$. Then the field of $G$-invariants, $K^G$, ...
David E Speyer's user avatar
8 votes
1 answer
461 views

Existence of at least one compact orbit on the sphere

Good morning, I've came across this question during my researches. It seems apparently very simple, however I Googled a bit and I couldn't find the answer I was looking for. The question is as ...
guido giuliani's user avatar
8 votes
0 answers
196 views

Does $\varphi: \mathbb{P}^{n} \to \mathbb{P}^{n}$ have periodic points missing the critical hypersurface?

I am trying to prove that if $\varphi: \mathbb{P}^{n} \to \mathbb{P}^{n}$ is an algebraic morphism of degree $d > 1$ (by which I mean $\varphi^{*}(\mathcal{O}(1)) = \mathcal{O}(d)$, so the ...
Alon Levy's user avatar
  • 113
6 votes
1 answer
443 views

Can the methods of algebra characterize nonlinear PDE blow-ups?

Consider 2 simple differential equations: $x'(t)=x(t)^2, x(0)=1$ and $x'(t)=-x(t)^2, x(0)=1$. As $t$ goes from $0$ to $\infty$, the first equation ($x(t)=1/(1-t)$) will lead to a finite-time blow-up, ...
Iza_lazet's user avatar
  • 179
6 votes
1 answer
320 views

Is there a canonical notion of principal divisor on a discrete dynamical system?

I hope this question is well-posed. Let (X, f) be a discrete dynamical system such that every x in X has finite period, i.e. there is some n such that f^n(x) = x. Let Div(X) be the free abelian ...
Qiaochu Yuan's user avatar
6 votes
0 answers
537 views

Counting limit cycles via curvature in Riemannian geometry

In this post we would like to give a possible new approach to the second part of the Hilbert 16th problem First we give a short introduction: A quadratic system is a polynomial vector field on ...
Ali Taghavi's user avatar
6 votes
0 answers
450 views

Differential equation of line tangent to caustics

This problem (or rather, statement that I cannot understand) has arisen in a paper I have been reading "Geometry of Integrable Billiards and Pencils of Quadrics" by Dragovic and Radnovic. I'd be most ...
A B's user avatar
  • 281
5 votes
2 answers
534 views

Examples of surface automorphisms with no periodic points

Consider a smooth projective complex surface $S$ with an automorphism $g:S\to S$. A point $p$ is periodic if it has finite orbit under iterates of $g$. What are some examples of surface ...
J.C. Ottem's user avatar
  • 11.6k
5 votes
1 answer
212 views

Stability of ODEs with polynomial nonlinearity

Consider the following ODE system: $$ x′=f(x)\iff \begin{pmatrix} x_1^\prime \\ \vdots\\ x_k^\prime\\ \vdots\\ x_n ^\prime \end{pmatrix} = \begin{pmatrix} f_1(x) \\ \vdots\\ f_k(x)\\ \vdots\\ f_n(x) \...
Zhang Yuhan's user avatar
5 votes
0 answers
140 views

Algebraic independence of limit cycles of Lienard equation

It is well known that the Van der Pol equation $$\begin{cases} \dot x=y-(x^3-x)\\\dot y=-x \end{cases}$$ has no an algebraic limit cycle. According to this fact, we search for a related ...
Ali Taghavi's user avatar
5 votes
0 answers
216 views

Dynamical Mordell-Lang on Kahler manifolds?

Suppose that $X$ is a smooth projective variety over $\mathbb C$ and $\phi : X \to X$ is an endomorphism. Let $p \in V$ be a point and $V \subset X$ a subvariety. The dynamical Mordell-lang ...
user avatar
5 votes
0 answers
303 views

Quantum dynamics on varieties: asymptotic quantum trace distance on SHL varieties

The Question Asked Definition: the Second-Hand Lion trace distance $D_k$ Let $\mathcal{M}^{(kk)}_r$ be the set of $k\times k$ complex matrices of rank $\le r$ having unit trace norm. Then the ...
John Sidles's user avatar
  • 1,389
4 votes
2 answers
291 views

Non-trivial surjective holomorphic selfmap of compact Kähler manifold of $\operatorname{dim} \geq 3$?

I am finding some nontrivial examples of surjective holomorphic selfmap of compact Kähler manifold of $\operatorname{dim} \geq 3$. That is, find $X$ a compact Kähler manifold of $\operatorname{dim} X \...
anonymousInd's user avatar
4 votes
1 answer
818 views

Spectral curve of Elliptic Calogero-Moser systems

First, why all the coefficients in the characteristic polynomial of L are elliptic functions, since the diagonal entries of the matrix L are the momentums? second, how to understand the ramification ...
Jimmy's user avatar
  • 77
4 votes
0 answers
339 views

Why are critical points important for dynamical systems?

I have just started reading a little about (arithmetic) dynamics and it seems like critical points are very important - for instance, rational maps so that critical points have finite forward orbit (...
Asvin's user avatar
  • 7,746
4 votes
0 answers
335 views

Algebraic Dynamics over separated schemes

I have a few questions regarding the current status of research on algebraic dynamics over separated schemes. In what follows $\varphi:X\rightarrow X$ will be a finite self-morphism of a noetherian ...
Mahdi Majidi-Zolbanin's user avatar
3 votes
1 answer
261 views

A question on dynamics on complex algebraic curves

Let $X$ be a complex algebraic curve, assumed to be connected, smooth and complete. Let $f: X \rightarrow X$ be a surjective morphism. Define a backward complete set for $f$ as a subset $S$ of $X$ ...
Joël's user avatar
  • 26k
3 votes
2 answers
271 views

Orbits under the automorphism group of projective space

Let $\mathbb{P}^d_K$ be projective space of dimension $d\geq 1$ over an infinite field $K$. Let $x\in\mathbb{P}^d_K$ with $\dim\overline{\lbrace x\rbrace}=n\leq d-1$. My question: is the set $\lbrace ...
Vector's user avatar
  • 133
3 votes
0 answers
213 views

Dynamical degree and spectral radius

Let $X$ be a smooth, projective surface over an algebraically closed field $k$ of characteristic zero, and let $f \in \mathrm{Bir}(X)$ a birational map. Let's denote $f_{\ast} : \mathrm{NS}(X) \...
Federico Barbacovi's user avatar
3 votes
0 answers
141 views

Which is the number of independent components of a flat spin connection in a 4 dimension Weitzenböck spacetime?

A spin connection $A_{ab\mu}=-A_{ba\mu}$ has 24 components. The number of independent components for a flat spin connection can be counted by subtracting the constrains set by the condition of null ...
asierzm's user avatar
  • 51
3 votes
0 answers
143 views

What is known about topological equivalence of polynomial dynamical systems on two different domains in R^n?

The question is mainly about $\it flows$, not maps (i.e., continuous time, not discrete time). Is it known if the study of polynomial dynamical systems on $\mathbb R^n$ can be reduced to the study of ...
DC47's user avatar
  • 111
3 votes
0 answers
88 views

Question about a length inequality in algebraic dynamics

Let $X$ be a Noetherian scheme. Let $f\colon X\rightarrow X$ be an integral self-morphism. If $x\in X$ is a closed point, I will write $\mathcal{F}_{1}^x$ for the coherent sheaf of $\mathcal{O}_X$-...
Mahdi Majidi-Zolbanin's user avatar
2 votes
1 answer
273 views

Is the exceptional set Zariski open?

Let $T$ be a smooth projective variety and $f_T : \mathbb {P}^N_T \rightarrow \mathbb {P}^N_T $ be a family of dominant rational maps. The dynamical degree of a dominant rational map $f $ is defined ...
LWW's user avatar
  • 663
2 votes
1 answer
139 views

Can a chaotic trajectory solve an algebraic equation?

Given a polynomial ODE in $n$-dimensions of maximal degree $d$ $$\dot{x}_j=f_j(x)=\sum_{i_{1},\dots,i_{n}=1}^{d}a_{i_{1},\dots,i_{n}}^{j}x_{1}^{i_{1}}\dots x_{n}^{i_{n}} \quad \forall j=1,...,n$$ we ...
NicAG's user avatar
  • 247
2 votes
0 answers
170 views

Symplectic structure on moduli space of holomorphic Abelian differentials

I've heard a "symplectic structure" referred to on the moduli space of holomorphic Abelian differentials by numerous people / sources. I do not know how to interpret this - I am looking for ...
John Rached's user avatar
2 votes
0 answers
101 views

Properties of algebraic vector fields which generates a $\mathbb{C^*}$ action

My question is rather vague and I apologize. Let $X$ be a smooth quasi-projective variety over $\mathbb{C}$. I am interested in whether there are homological properties which distinguish algebraic ...
user36931's user avatar
  • 1,331
1 vote
2 answers
391 views

Orbits of rational functions

This is a generalization of Integrality of iterates of rational functions. The question is: given an infinite sequence of rational numbers $a_0, a_1, \dotsc, a_n, \dotsc,$ is it always an orbit of $...
Igor Rivin's user avatar
  • 96.4k
1 vote
1 answer
476 views

Two limit cycles which lie on the same leaf

Edit 1: For a related discussion see this MSE post I apologize in advance, if this question is obvious: 1)What is an example of a polynomial vector field on $\mathbb{R}^{2}$ with at least two ...
Ali Taghavi's user avatar
1 vote
1 answer
233 views

Vector fields whose divergence are proper maps

Let $X$ be a polynomial vector field of degree $2$ on $\mathbb{R}^{2}$. Does there exist a nonvanishing smooth function $g$ such that $Div(gX)$ is a proper map?Or at least the zero locus of $Div(...
Ali Taghavi's user avatar
1 vote
1 answer
308 views

Holomorphic representations of complex reductive Lie groups and the boundary of orbits (Reference request)

I have difficulties finding an appropriate reference for the following question (which I hope that it to be true). Let $U$ be a compact Lie group, $G:=U^{\mathbb{C}}$ its complexification and $\tau: U^...
Juanita Villa's user avatar
1 vote
0 answers
72 views

Equivalence between smoothly regular and analytically regular

I think the following statement is true. Let $M$ be a real analytic manifold. Let $S \subset M$ be an analytic or semianalytic subset. A point $p \in S$ is called smoothly regular resp. analytically ...
UVIR's user avatar
  • 803
1 vote
0 answers
92 views

Computing algebraic entropy

Could you recommend any reference for computing algebraic entropy? Here algebraic entropy is defiened as $\lim_{n \to \infty}\log (deg (f^n))^{1/n}$ for a rational map $f $. I saw that there are ...
LWW's user avatar
  • 663
1 vote
0 answers
403 views

Weakened jacobian conjecture for entire functions

A rudin's theorem is the assertion that any polynomial injection between affine spaces of the same dimension has a polynomial inverse, and the inverse is also given by polynomials. The jacobian ...
Koushik's user avatar
  • 2,106
1 vote
0 answers
242 views

How Markus–Yamabe implies Jacobian ?

To make myself precise, I would like to recall some backgrounds. (Markus-Yamabe, $\mathrm{MY}_n$) Given a $C^1$ map $f:\Bbb R^n \to \Bbb R^n$ with $f(0)=0$ and $Df$ everywhere Hurwitz stable (the ...
Zhang Xiao's user avatar
1 vote
0 answers
225 views

Functions holomorphic on a region minus a Cantor set - pt.2: Iterated function systems

This post is a follow up to my previous question enquiring whether it is always possible to extend a homeomorphism conformal on a region $R$ minus a Cantor set to the whole of $R$. From the answers I ...
uncooltoby's user avatar
0 votes
0 answers
70 views

Example of DS with a dense trajectory in the whole state space

Let $U \subset \mathbb{R}^n$ be an open and connected set. We assume there is a vector field $F \in \mathcal{C}^1(\overline{U})$ giving rise to a DS ($\overline{U}$ denotes the closure) $$\dot{\mathbf{...
NicAG's user avatar
  • 247
0 votes
0 answers
261 views

Is an immersed Kronecker join always a multilinear variety on a Hilbert space?

The question asked is: Is the implicitization of an arbitrary-rank immersed Kronecker join always a multilinear variety on a Hilbert space? This is related to another MathOverflow question In ...
John Sidles's user avatar
  • 1,389
-3 votes
1 answer
2k views

Quantum dynamics on varieties and Salmon Prizes

Concluding Progressive Remarks A new finding is Bates and Oeding's preprint "Toward a salmon conjecture" (arXiv:1009.6181), with its reference to the Salmon Prize. The Salmon Prize (photo of the ...