# Talk:Action-angle coordinates

I believe that the author of the article confused the notation when talking about the action-angle variables. In particular, the variable ${\displaystyle \mathbf {w} }$ is generally called the angle and ${\displaystyle \mathbf {J} }$ is the action. I would like to correct this if there are no objections. Also, one should probably indicate that the derivation holds only for separable ${\displaystyle S}$ in proper separated coordinates ${\displaystyle q_{i}}$. PtolRek (talk) 20:44, 15 October 2010 (UTC)