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Pfief
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Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect a structurally similar result as in the initial value case, though this case is technically more delicate. Any help or key word that hints in the right direction is appreciated, as I am no expert in this field.

EDIT: An approach that came to my mind is to prove that there exists some kind of linearisation which is valid in a very small ball $B_\delta(0)$ that does NOT depend on $p$. Given this, one can smoothly change the coordinates in this area.

Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect a structurally similar result as in the initial value case, though this case is technically more delicate. Any help or key word that hints in the right direction is appreciated, as I am no expert in this field.

EDIT: An approach that came to my mind is to prove that there exists some kind of linearisation which is valid in a very small ball $B_\delta(0)$ that does NOT depend on $p$. Given this, one can smoothly change the coordinates in this area.

Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect a structurally similar result as in the initial value case, though this case is technically more delicate. Any help or key word that hints in the right direction is appreciated, as I am no expert in this field.

EDIT: An approach that came to my mind is to prove that there exists some kind of linearisation which is valid in a ball $B_\delta(0)$ that does NOT depend on $p$. Given this, one can smoothly change the coordinates in this area.

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Pfief
  • 11
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Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect a structurally similar result as in the initial value case, though this case is technically more delicate. Any help or key word that hints in the right direction is appreciated  , as I am no expert in this field.

EDIT:) An approach that came to my mind is to prove that there exists some kind of linearisation which is valid in a very small ball $B_\delta(0)$ that does NOT depend on $p$. Given this, one can smoothly change the coordinates in this area.

Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect a structurally similar result as in the initial value case, though this case is technically more delicate. Any help or key word that hints in the right direction is appreciated  :)

Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect a structurally similar result as in the initial value case, though this case is technically more delicate. Any help or key word that hints in the right direction is appreciated, as I am no expert in this field.

EDIT: An approach that came to my mind is to prove that there exists some kind of linearisation which is valid in a very small ball $B_\delta(0)$ that does NOT depend on $p$. Given this, one can smoothly change the coordinates in this area.

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Pfief
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Smoothness of unstable manifold near (non?)-hyperbolic fixed point w.r.t. generator of the flow

Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect somethinga structurally similar result as in the initial value case, but google did not provide any answer so farthough this case is technically more delicate. Any help or key word that hints in the right direction is appreciated :)

Smoothness of unstable manifold near (non?)-hyperbolic fixed point

Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect something as in the initial value case, but google did not provide any answer so far. Any help or key word that hints in the right direction is appreciated :)

Smoothness of unstable manifold near (non?)-hyperbolic fixed point w.r.t. generator of the flow

Consider a dynamical system $\dot{x} = f(x,p)$, where $p \in R^n$ is a bunch of parameters and $f$ is a smooth function, both in $x$ and $p$. Given an initial value problem where $x(0) = x_0$, it can easily be seen that any bounded solution on a finite time-interval is continuous w.r.t. $p$ (proof by Gronwall-estimate).

But what happens when we consider the unstable manifold of a fixed-point? For simplicity, lets consider $f(0,p) = 0 \, \forall p$, and $0$ has an unstable manifold $M^-_p$ of dimension $1$ for all $p$. Given some $p_0$ and a bounded segment of $M^-_{p_0}$ that includes $0$, is there any sort of continuity as we change $p$?

I expect a structurally similar result as in the initial value case, though this case is technically more delicate. Any help or key word that hints in the right direction is appreciated :)

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Pfief
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