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8 votes
2 answers
1k views

What is the current status on methods to find limit cycles?

What are the current best methods to show analytically the existence of a limit cycle in a $n$-dimensional system of the form: $$ \frac{\mathrm{d}}{\mathrm{d} t} \vec{x}(t)=\vec{f}(\vec{x}) $$ Where $...
Matt's user avatar
  • 117
7 votes
1 answer
453 views

How to study the global stability for this 3D system?

I am studying a biological system (HIV) and arrived at this simplified dynamical system: \begin{align} x_1' &= a_1 + a_2x_2 - a_1x_2 - a_4x_1 - a_5\frac{1+a_6x_3}{1+a_7x_3}x_1\\ x_2' &= a_5\...
Paichu's user avatar
  • 513
7 votes
1 answer
930 views

(In)stability of a two-dimensional dynamical system

Consider the following system of coupled differential equations \begin{eqnarray*} \dot{x}_1(t) & = & -x_1(t) - \cos(\omega t)x_1(t) + \cos(\omega t)x_2(t), \ x_1(0)\in\mathbb{R},\\ \dot{x}_2(t)...
Ludwig's user avatar
  • 2,712
5 votes
1 answer
211 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
2 answers
828 views

Conditions for convergence to non-isolated fixed points

Consider a dynamical system of the form $$ \dot{x}=f(x), \quad x\in X, $$ and assume that the system possesses a set of non-isolated fixed points. Suppose moreover that there exists a Lyapunov $V(x)$ ...
Ludwig's user avatar
  • 2,712
5 votes
0 answers
281 views

Basin of attraction of gradient flow

Suppose we have a compact Riemannian manifold $(M,g)$, and a Morse function $f : M \rightarrow \mathbb{R}$. Suppose we consider the gradient flow generated by this function, i.e. $$\dot{x_t} = - \...
Rikimaru's user avatar
  • 151
4 votes
1 answer
211 views

How many different states of Nash equilibrium?

So there is this quite well known Prisoner's dilemma where two parties can both defect and cooperate (and get points based on their decisions). In my presently used example I take it that cooperating ...
Pranasas's user avatar
  • 143
4 votes
1 answer
90 views

Do Pareto critical points of a multicriteria optimization problem form an attractor of the dynamical system induced by a descent algorithm?

Let $d\in\mathbb N$, $k\in\mathbb N$ and $f:\mathbb R^d\to\mathbb R^k$ be differentiable. Say that $v\in\mathbb R^d$ is a descent direction at $x\in\mathbb R^d$ if ${\rm D}f(x)v<0$ (component-wise) ...
0xbadf00d's user avatar
  • 167
4 votes
0 answers
108 views

The logistic elliptic equation

Studying the Fisher-KPP evolution equation I came across the steady state elliptic problem which can be written in the following form: $$ \begin{cases} -d\Delta Y(x)=r(x)Y(x)\left (1-\dfrac{Y(x)}{K(x)}...
Bogdan's user avatar
  • 1,759
4 votes
0 answers
142 views

KAM stable orbits are smooth

I'm in my final year of my undergraduate studies doing work on modelling the n-body problem numerically and I also have some interest in theoretical guarantees. Now, I've been looking for a theorem ...
Aidan Rocke's user avatar
  • 3,871
3 votes
2 answers
428 views

Nonlinear ODE system: stability

I've got this 4x4 system that should model the wine fermentation process. All the $\mu, K_N, k_d$ etc are positive constants. Of course I have no idea of how to solve it. But at least I would like to ...
7iat's user avatar
  • 31
3 votes
1 answer
202 views

Stability of nonsmooth, Lipschitz continuous, autonomous system of differential equations

Consider the following autonomous system of differential equations: $$\frac{\mathrm d\mathbf x}{\mathrm dt} = \mathbf v(\mathbf x)$$ where $\mathbf x, \mathbf v \in \mathbb R^n$. Assume that $\...
valle's user avatar
  • 884
3 votes
1 answer
197 views

Exact solution to a periodic linear ODE sought

We have been studying a Hamiltonian system that possesses a one-parameter family of periodic orbits, depending on the energy level $h$. We "know" via various non-rigorous means that these ...
Roy Goodman's user avatar
3 votes
1 answer
176 views

Is the convergence of $\dot{x}=2A(t)x$ faster than that of $\dot{x}=A(t)x$?

Let $x \in \mathbb{R}^{n}$ and $A(t) \in \mathbb{R}^{n\times n}$. If $\dot{x}=A(t)x$ and $\dot{x}=cA(t)x$ with $c>1$ are exponentially stable. Is the convergence rate of $x$ to zero of $\dot{x}=cA(...
guluzhu's user avatar
  • 33
3 votes
1 answer
252 views

Stability analysis of equilibrium point of non-linear ODE system with Jacobian going to infinity

Let's say I have a nonlinear system of ODEs, where one of equations looks like: $$ \frac{dX_i}{dt} = a_1X_0+\dotsb+a_j\frac{X_j^{0.5}}{X_j^{0.5}+b_j^{0.5}}+\dotsb. $$ And equilibrium point is 0. I ...
Omega's user avatar
  • 31
3 votes
1 answer
196 views

Stable periodic orbits for three equal masses

For three equal masses in any number of dimensions (this might not be important, but 2D or 3D or 4D is fine) under just classical gravity (i.e., inverse-square force law), what stable periodic orbits ...
bobuhito's user avatar
  • 1,547
3 votes
0 answers
107 views

Stability of a nonlinear dynamical system with non-elementary dynamics

I am trying to prove stability and get a non-asymptotic upper bound on the convergence rate of a nonlinear discrete-time dynamical system, whose dynamics are stated in terms of the (non-elementary) ...
mtcrawshaw's user avatar
3 votes
0 answers
50 views

Stability of indefinitely damped mechanical system with diagonal stiffness

I'm trying to find conditions for the asymptotic stability of the following linear system, \begin{equation} \mathbf{I \ddot{x}} + \mathbf{B \dot{x}} + \mathbf{K x} = 0 \end{equation} given the ...
Shivang Rawat's user avatar
3 votes
0 answers
134 views

Asymptotic behaviors of equilibrium points of a switching SDE with Levy jumps?

Consider the following paper titled: Stochastic regime switching SIR model driven by Lévy noise, authored by Yingjia Guo. Link: https://www.sciencedirect.com/science/article/pii/S0378437117302145 The ...
Math's user avatar
  • 185
3 votes
0 answers
65 views

Uniform stability of linear operators - reference request

Let $T$ be a bounded linear operator on a complex Banach space $X$. I am looking for a reference for the following result: Theorem 1. Let $p \in [1,\infty]$. The following assertions are equivalent: (...
Jochen Glueck's user avatar
3 votes
0 answers
82 views

conditions for asymptotic comparison to hold

I have the following simple dynamical system: \begin{align} x_1' &= a - f(x_2)x_1\\ x_2' &= bx_1 - cx_2, \end{align} where all parameters and initial conditions are positive. $f(x_2)$ is a ...
Paichu's user avatar
  • 513
2 votes
1 answer
239 views

Seeking a Lyapunov function for a SIR model with immunity loss

We add the immunity loss to the SIR model and obtain the following autonomous system. $$ \begin{align} s' &= -is+\alpha r \\ i' &= i s - \gamma i\\ r' &= \gamma i-\alpha r \end{align} \...
Hans's user avatar
  • 2,239
2 votes
1 answer
134 views

On local attractivity of a coupled non-linear differential equation

Consider a dynamical system described by the following coupled non-linear differential equation \begin{align} \dot{x}_1(t) &= v + a_{12}\sin(x_2(t)-x_1(t)) + a_{13}\sin(x_3(t)-x_1(t))\\ \dot{x}_2(...
Ludwig's user avatar
  • 2,712
2 votes
3 answers
1k views

Non-linear state-space model system stability using Lyapunov?

I have a non-linear system modelled in state-space as follow: $$ \mathbf {\dot x} = \mathbf A(x) \mathbf x $$ I need to find out if this system is stable, so I was thinking in using the Lyapunov ...
pablogh's user avatar
  • 31
2 votes
1 answer
102 views

Norm bound in simultaneous stability to semidefinite program

In the context of robust control, I remember hearing that the two following problems are equivalent. Find $P \succ 0$, such that $A P + P A^{\top} \prec 0$ for all $A \in \mathscr{A}$ where $$\...
patchouli's user avatar
  • 275
2 votes
1 answer
132 views

Is there any foster-Lyapunov criterion for time varying Markov processes?

Suppose I have 2 Markov processes with transition kernels Q_1(y|x) and Q_2(y|x). Suppose i also have Lyapunov functions V_1, V_2 for these processes w.r.t. a common set, i.e. there exists a compact ...
Deepanshu Vasal's user avatar
2 votes
1 answer
674 views

Center manifold theorem and case of all zero eigenvalues

Is the center manifold theorem applicable if say for a planar (2D) system of non-linear ODE, the stability matrix has both eigenvalues zero? Of course, there is only one eigenvector. If not, what is ...
Subho's user avatar
  • 121
2 votes
1 answer
65 views

Boundedness of particle motion with time-varying force

Consider the differential equation $$ m \ddot{x} + k \dot{x} = - W_t x $$ where $m$ and $k$ are nonnegative. $x_t \in \mathbb{R}^n$ $W_t$ is a matrix that satisfies $$ \alpha I \succeq W_t \...
Michael S.'s user avatar
2 votes
0 answers
48 views

Characterization of multifunctions with globally asymptotically stable minimal invariant sets

Let $(X, d)$ be a compact connected metric space. Consider a compact-valued upper semicontinuous multifunction $F: X \rightrightarrows X$. The reachable set $R[x]$ of $F$ from $x\in X$ is defined as: ...
David Dai's user avatar
  • 111
2 votes
0 answers
60 views

Identifying bifurcation

[![enter image description here]] 1]1I am trying to analyze the bifurcation of a 3D continuous model. For a certain range of parameter values, the origin is always an unstable point, whereas the ...
SHR's user avatar
  • 53
2 votes
0 answers
65 views

Where can I find resources for a paper "Stability analysis of a novel DDE of HIV CD4+ T-cells"?

I am currently working on a the paper [NND]: Question: On page 4, equation 6 introduces a concept related to the infection rate within the context of the HIV model. Unfortunately, the paper does not ...
Furdzik Zbignew's user avatar
2 votes
0 answers
153 views

Stability test for LTV systems by differential Lyapunov inequalities

Consider a linear time-varying system: \begin{equation} \dot x(t) = A(t) x(t), \tag{$*$} \end{equation} where $A(t)$ is a time-varying block matrix defined as $$ A(t) = \begin{bmatrix} 0 & I\\ -\...
Evan's user avatar
  • 55
2 votes
0 answers
83 views

Center-stable manifold theorem on manifold with boundary

I would like to see if there is a Center-stable manifold theorem on the phase space that is a manifold with boundary. Suppose $f:M\rightarrow M$ is a diffeomorphism, according to Theorem III.7 in "...
Xiiao's user avatar
  • 21
2 votes
0 answers
94 views

Stability of dynamical system via Lyapunov

I have a dynamical system which has the following form: $\dot x=\mathcal F_1(m_1)x+\mathcal F_2(m_2)x$. My objective is to find the parameters $m_1$ and $m_2$ via LMI (linear matrix inequality) using ...
khallouq abdelmounaim's user avatar
2 votes
0 answers
65 views

Exponential Convergence Under a Lyapunov-Like Assumption

Consider $V=\mathbb{R}^d\times\mathbb{R}^n$ with coordinate $x^T=[\theta^T,\sigma^T]$. I have an ODE of the form: $\dot{x}=F(x)$, where $F$ is assumed to be sufficiently smooth. Suppose that there's ...
Miel Sharf's user avatar
1 vote
1 answer
321 views

Marginal stability of discrete linear time-invariant system

I have a question about marginal stability of a system: \begin{equation} \mathbf{x}[k] = \mathbf{A}\mathbf{x}[k-1] \end{equation} I would adapt the definition of marginal stability from this ...
Slaven Glumac's user avatar
1 vote
1 answer
237 views

Stability of a system of ODEs

It is well known that for a system of ODEs, $\dot{\boldsymbol{y}} = \boldsymbol{Ay}$, the global stable equlibrium point is given by the eigenvector that correponds to the largest eigenvalue of $\...
Jeff's user avatar
  • 19
1 vote
0 answers
63 views

Stability Problem in a Nonlinear Dynamical System

Consider the nonlinear dynamical system given by the following differential equations \begin{cases} \dot{x} = y, \\ \dot{y} = x - x^3 - \gamma y + \delta x^2 y. \end{cases} I want to demonstrate that, ...
felcove's user avatar
  • 31
1 vote
0 answers
53 views

The Frobenius integrability of distrbution and Hyers–Ulam–Rassias stability

Let $M$ be a compact Riemannian manifold. The norm of vector fields are computed with respect to the metric. Moreover for every distribution $D$, the orthogonal projection on $D$ is ...
Ali Taghavi's user avatar
1 vote
0 answers
63 views

Identifying Saddle-node bifurcation of a 3D system of ODEs

I am trying to understand and prove the results shown in the following article. However, I am stuck at a point where it is stated that saddle-node bifurcation of periodic orbits occurs at ...
SHR's user avatar
  • 53
1 vote
0 answers
53 views

Basin of attraction comparative statics* using local energy functions?

Let $\dot{\boldsymbol{x}}=\boldsymbol{F}(\boldsymbol{x};p)$ be an autonomous dynamical system defined on $[a,b]^n$ ($-\infty<a<B<\infty)$; $p\in\mathbb{R}$ is some fixed parameter. Suppose ...
cluelessmathematician's user avatar
1 vote
1 answer
151 views

Analytically characterizing basins of attraction boundaries and sizes

While I understand that doing the above is not possible in general, I would like to know more about how to proceed when it is possible. That is, what are the common methods people use to analytically ...
cluelessmathematician's user avatar
1 vote
0 answers
98 views

Clarification on the proof of Lyapunov-Razumikhin asymptotic stability theorem for delayed differential equations

this is my first question here, hope I am in the right place :) Recently I have been looking at the proof of theorem 4.2 on Razumikhin stability for RFDEs in the book by Jack Hale and Lunel Verduyn: ...
Adriano Mele's user avatar
1 vote
0 answers
34 views

$L^p$-continuity for discrete linear causal systems

Let $p \in [1, +\infty)$, $(b_0(n)), \dots (b_m(n)), (a_1(n)), \dots, (a_m(n))$ suitable sequences of real numbers and consider the map $\phi: \ell^p \to \ell^p$, $x \mapsto y$ defined by: \begin{...
avril_14th's user avatar
1 vote
0 answers
157 views

Selecting a suitable Lyapunov function for the following systems?

i) SI MODEL Consider \begin{align} \frac{dS}{dt} &= \mu N -\frac{\beta S I}{N} - \nu S\\[2ex] \frac{dI}{dt} &= \frac{\beta S I}{N} -\nu I \end{align} Where $N=S+I$ is the total population. If ...
Math's user avatar
  • 185
1 vote
0 answers
181 views

Subset of the domain of attraction

Let $x \in R^n$ and $f : R^n \to R^n$, $f\in C^1$ $$ \frac{\mathrm{d}}{\mathrm{d}t} x(t) = f(x(t)) $$ be such that $f(0) = 0$ is asymptotically stable. The domain of attraction is the set of initial ...
SampleTime's user avatar
1 vote
0 answers
62 views

Lyapunov theory in coupled nonlinear dynamic system with input

Suppose I have the following nonlinear coupled dynamic system \begin{align*} &\dot{x}_1 = f_1(x_1,x_2)\\ &\dot{x}_2 = f_2(x_2) + u \end{align*}where $x_1\in \mathbb{R}^{n_1}$, $x_2\in \mathbb{...
sleeve chen's user avatar
1 vote
0 answers
44 views

Sufficient conditions for the continuity of an improper integral concerning the finite-time stability of a dynamical system

Consider the initial value problem \begin{equation}\label{fainait ve} \dot{\boldsymbol{x}}(t) = \boldsymbol{f}(\boldsymbol{x}(t)), \;\; t \geq 0, \; \;\boldsymbol{f}(\boldsymbol{0}_n) = \boldsymbol{0}...
Johannes's user avatar
1 vote
0 answers
67 views

Stability of a continuous piecewise linear map

I am studying random perturbation of a system that is continuous and piecewise linear. More precisely: I am given a map $\Phi_1:\mathbb{R}^d\to \mathbb{R}^d$ such that $$ \Phi_1(x) = \left\{\begin{...
N. Gast's user avatar
  • 562
1 vote
0 answers
89 views

Lower bounds of kappa class functions

I saw in the paper "Smooth Satabilization Implies Coprime Factorization" of Eduardo Sontag the following argument: Given a smooth map $a:\mathbb{R} ^{n}\rightarrow\mathbb{R}^{+}$, let $\rho$ be any ...
UnclePetros's user avatar