Questions tagged [dynamical-systems]
In dynamical systems, the motion of a particle in some geometric space, governed by some time dependent rules, is studied. The process can be discrete (where the particle jumps from point to point) or continuous (where the particle follows a trajectory). Dynamical systems is used in mathematical models of diverse fields such as classical mechanics, economics, traffic modelling, population dynamics, and biological feedback.
7,438 questions
3 votes
0 answers
86 views
Integer sequence with largest prime factor
Consider the function $F:\mathbb{N}\to\mathbb{N}$ such that $F(n)=\tfrac{n^2-n}{\delta(n^2-n)}$, where $\delta$ returns the biggest prime factor of its input. I wonder if this function always ...
1 vote
0 answers
86 views
Reference request: a particular generalization of the Collatz problem
This is a reference request; is this particular generalization of the $3\cdot n+1$ problem discussed in literature? What is known about it? Do any specific choices of $m$, $a_i$ lead to nontrivial yet ...
3 votes
1 answer
147 views
Determining stability of the equilibrium point for a nonlinear system
Consider a system \begin{align} &\frac{dx}{dt}=y\\ &\frac{dy}{dt}=-y^2-\sin x \end{align} (0,0) is an equilibrium, and I want to know whether it is Lyapunov stable. If it is stable, then is it ...
2 votes
1 answer
155 views
Why does the Generalized Collatz map ($3n+k$) with $k=3^x+2^x$ produce 1,023 cycles at $x=15$, but collapse to 1 cycle for $x \ge 21$?
I have been investigating the number of limit cycles (loops) in the Generalized Collatz Problem defined by the map:$$T_k(n) = \begin{cases} (3n+k)/2 & \text{if } n \text{ is odd} \\ n/2 & \...
2 votes
1 answer
40 views
Periodic Orbits of Arbitrarily Small Period for a Flow Without Fixed Points
Question: Let $\varphi_t: M \to M$ be a continuous flow with no fixed points on a compact metric space $M$. If $\varphi_t$ has a periodic orbit, is there a positive lower bound on the period of all ...
0 votes
0 answers
43 views
Study of non linear dynamical system
I am interested in the following non-linear system of ODEs (all the parameters are positive): $$ dR_{1,t}=-\lambda_1 R_{1,t}\,dt + C\,(\beta_0-\beta_1 R_{1,t} + \beta_2 \sqrt{R_{2,t}})\, dt $$ $$ dR_{...
0 votes
0 answers
52 views
Can we determine whether the binary sequence we obtain through this equation has ever more ones than twice the zeros?
Suppose we define a binary sequence $\varepsilon _{k}$ such that it satisfies the equation $$\varepsilon _{k} =\left\lceil \left(\frac{3}{2}\right)^{k}\left( 8-\frac{1}{3}\sum _{j=0}^{\infty }\left(\...
0 votes
0 answers
33 views
Prove that $(X,T^k)$ is uniquely ergodic [closed]
Suppose that $X$ is a compact metric space with metric $d$ and $T:X\to X$ is continuous. Assume that $(X,T)$ is uniquely ergodic with the Borel probabilistic measure $\mu$ and $(X,\mathcal{B}(X),\mu,...
0 votes
0 answers
62 views
What is the name of the property of $x\mapsto 3f(x)$ that its orbits are wellordered by $f$? [closed]
Consider the dynamical map that terminates on all natural numbers: $f_o:x\mapsto (x+1)/2$ if $x$ odd $f_e:x\mapsto x/2$ if $x$ even This is easily proven to terminate for all natural numbers. Now ...
1 vote
0 answers
132 views
Is the reverse bit shift map times $3^n$ guaranteed to have sequences with no further multiples of $3$?
Question The dynamical system: Let $f(x)=\begin{cases}(x+1)/2&&x\textrm{ odd}\\x/2&&x\textrm{ even}\end{cases}$ is the the bit shift map with binary strings reversed. It terminates ...
1 vote
0 answers
50 views
Prove that exists an heteroclinic orbit
I have the following system: \begin{cases} \dot{x}=x-y,\\ \dot{y}=x^2-4 \end{cases} The point (2,2) is an unstable spiral and (-2,-2) is an saddle point. I know they are connected ...
0 votes
1 answer
38 views
Can even periodic points of a map undergo tangent bifurcation?
My intuition for the answer is NO, here is my thought: Let $T(x,\lambda)$ be the map depending on one parameter $\lambda$, assume at $(x_0,\lambda_0)$ a tangent bifurcation occurs for the $T^2$ map, ...
1 vote
0 answers
95 views
Definition of $C^{1}$ on closure of open set
Let $X$ and $Y$ be Banach spaces. Let $U$ be an open subset of $X$ and $f:A\rightarrow Y$ be a function with $U\subseteq A\subseteq\overline{U}$. Then we have two possible definitions of $f\in C^{1}(A,...
7 votes
1 answer
84 views
Does a dense orbit imply topological transitivity for flows on manifolds?
Let $M$ be a smooth connected manifold of dimension $\geq 2$, and let $\phi: \mathbb{R} \times M \to M$ be a complete flow on $M$. Suppose there exists a point $x_0 \in M$ whose orbit is dense in $M$, ...
2 votes
0 answers
104 views
Does multi-rate update depth bound the Volterra degree?
Fix a discrete-time system with input sequence $(x_t)_{t\ge 0}\subset\mathbb{R}^d$, output $(y_t)_{t\ge 0}\subset\mathbb{R}^p$, and $L$ internal levels. For each level $\ell\in\{1,\dots,L\}$ choose a ...