Skip to main content
4 events
when toggle format what by license comment
Aug 10 at 11:07 comment added Robert Bryant Consider the example of the $2$-sphere with its standard area form as symplectic struture. Now let $F = (f_1):S^2\to\mathbb{R}$ be any non-constant smooth function. I assume that meets your criterion as an integrable system, and the image of $F$ is an interval in $\mathbb{R}$. However, in general the flow of the Hamiltonian vector field on $S^2$ that corresponds to $f_1$ will not be periodic. You need that flow to be periodic or it won't come from a circle action. It's easy to construct higher dimensional examples by taking products.
Aug 9 at 18:43 comment added Michael Hardy I changed $2n-$dimensional to $2n$-dimensional, fixing this conspicuous typographical error.
Aug 9 at 18:39 history edited Michael Hardy CC BY-SA 4.0
added 3 characters in body
Aug 9 at 14:07 history asked Nicolas Medina Sanchez CC BY-SA 4.0