Arnold 9: Canonical Formalism#

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Manim Community v0.18.0

Manim Community v0.18.0

This document contains some random notes and discussions about Chapter 9 of [Arnol'd, 1989].

§44 The integral invariant of Pointcaré-Cartan#

In 3D, every vector field has a curl \(\vect{r} = \vect{\nabla}\times \vect{v}\), and one can find the integral curves of these, which Arnold calls vortex lines. Since \(\vect{\nabla}\cdot \vect{r} = 0\), these vortex lines have no “source”, hence flux is conserved. They need not form closed loops.

Here we plot some

def v(x, y, z):
    """Return a 3D vector field."""
    return (y, z, x)