Real dynamics of a family of plane birational maps: trapping regions and entropy zero

Dynamics of a two parameter family of plane birational maps: maximal entropy

We consider the real dynamics of a two parameter family of plane birational maps, focusing especially on an open subset of parameter space on which the real and complex dynamics are in close agreement. On the complex side, we find a rational complex surface to which the maps extend in a well-defined fashion and then calculate the induced action on the Picard group of the surface. On the real side, we use the critical sets of the maps to produce a combinatorial model for the dynamics. By comparing the two points of view, we are able to code points in the real non-wandering set, describe the beh…

Periodicities in Linear Fractional Recurrences: Degree growth of birational surface maps

We consider the set of all 2-step recurrences (difference equations) that are given by linear fractional maps. These give birational maps of the plane. We determine the degree growth of these birational maps. We find the all the maps in this family that are periodic. This also leads to new surface automorphisms with positive entropy.

Dynamics of (Pseudo) Automorphisms of 3-space: Periodicity versus positive entropy

We study the iterative behavior of the family of 3-step linear fractional recurrences and the family of birational maps they define. We determine all the possible periodicities within this family or, equivalently, the birational maps of finite order. This family also contains pseudo-automorphisms of infinite order. One such family consists of completely integrable maps, and another family consists of maps of positive entropy. Both of these families have invariant families of $K3$ surfaces.

Birational automorphism groups and the movable cone theorem for Calabi-Yau manifolds of Wehler type via universal Coxeter groups

Thanks to the theory of Coxeter groups, we produce the first family of Calabi-Yau manifolds $X$ of arbitrary dimension $n$, for which $\Bir(X)$ is infinite and the Kawamata-Morrison movable cone conjecture is satisfied. For this family, the movable cone is explicitly described; it's fractal nature is related to limit sets of Kleinian groups and to the Apollonian Gasket. Then, we produce explicit examples of (biregular) automorphisms with positive entropy on some Calabi-Yau manifolds.

Entropy of meromorphic maps and dynamics of birational maps

We study the dynamics of meromorphic maps for a compact Kaehler manifold X. More precisely, we give a simple criterion that allows us to produce a measure of maximal entropy. We can apply this result to bound the Lyapunov exponents. Then, we study the particular case of a family of generic birational maps of P^k for which we construct the Green currents and the equilibrium measure. We use for that the theory of super-potentials. We show that the measure is mixing and gives no mass to pluripolar sets. Using the criterion we get that the measure is of maximal entropy. It implies finally that the…

Dynamics and periodicity in a family of cluster maps

The dynamics of a 1-parameter family of cluster maps $φ_r$ associated to mutation-periodic quivers in dimension 4, is studied in detail. The use of presymplectic reduction leads to a globally periodic symplectic map, and this enables us to reduce the problem to the study of maps belonging to a group of symplectic birational maps of the plane which is isomorphic to $SL(2,\mathbb{Z})\ltimes\mathbb{R}^2$. We conclude that there are three different types of dynamical behaviour for $φ_r$ characterized by the integer parameter values $r=1$, $r=2$ and $r>2$. For each type, the periodic points, the st…

关于镜面捕获光线族的研究

On the trapping of ray families by mirrors

该研究解决Serge Tabachnikov的两个镜面捕获光线问题，证明ℝⁿ中被捕获光线族最大维数为2n-3，且ℝ³中存在不局部正交于光滑曲面的2参数被捕获光线族。

光滑仿射二次三维簇的一些有趣双有理态射

Some interesting birational morphisms of smooth affine quadric $3$-folds

本文研究复光滑仿射二次三维簇上一族多项式诱导的双有理映射，揭示其上同调双曲性、非代数整数的第二动力学度及周期点增长与代数熵的差异，并结合 Bertini 实验验证。

Quiet sigma delta quantization, and global convergence for a class of asymmetric piecewise affine maps

In this paper, we introduce a family of second-order sigma delta quantization schemes for analog-to-digital conversion which are `quiet' : quantization output is guaranteed to fall to zero at the onset of vanishing input. In the process, we prove that the origin is a globally attractive fixed point for the related family of asymmetrically-damped piecewise affine maps. Our proof of convergence is twofold: first, we construct a trapping set using a Lyapunov-type argument; we then take advantage of the asymmetric structure of the maps under consideration to prove convergence to the origin from wi…

Some integrable maps and their Hirota bilinear forms

We introduce a two-parameter family of birational maps, which reduces to a family previously found by Demskoi, Tran, van der Kamp and Quispel (DTKQ) when one of the parameters is set to zero. The study of the singularity confinement pattern for these maps leads to the introduction of a tau function satisfying a homogeneous recurrence which has the Laurent property, and the tropical (or ultradiscrete) analogue of this homogeneous recurrence confirms the quadratic degree growth found empirically by Demskoi et al. We prove that the tau function also satisfies two different bilinear equations, eac…

Dynamics of Rational Surface Automorphisms: Linear Fractional Recurrences

We consider the family $f_{a,b}(x,y)=(y,(y+a)/(x+b))$ of birational maps of the plane and the parameter values $(a,b)$ for which $f_{a,b}$ gives an automorphism of a rational surface. In particular, we find values for which $f_{a,b}$ is an automorphism of positive entropy but no invariant curve. The Main Theorem: If $f_{a,b}$ is an automorphism with an invariant curve and positive entropy, then either (1) $(a,b)$ is real, and the restriction of $f$ to the real points has maximal entropy, or (2) $f_{a,b}$ has a rotation (Siegel) domain.

Quadratic Planar Differential Systems with Algebraic Limit Cycles via Quadratic Plane Cremona Maps

In this paper we show how we can transform quadratic systems into new quadratic systems after some kind of birational transformations, the quadratic plane Cremona maps. We afterwards apply these transformations to the families of quadratic differential systems having an algebraic limit cycle. As a consequence, we provide a new family of quadratic systems having an algebraic limit cycle of degree 5. Moreover we show how the known families of quadratic differential systems having an algebraic limit cycle of degree greater than four are obtained using these transformations. We also provide the ph…

代数动力学与递归不等式

Algebraic dynamics and recursive inequalities

本文提出计算动力度的首个算法，证明动力度下半连续性和周期点稠密性，并证明 Kawaguchi-Silverman 猜想于一类射影曲面，核心工具是递归不等式。