An action with 
. Flows are generated by vector
fields and vice versa.
Flow
See also
Action, Ambrose-Kakutani Theorem, Anosov Flow, Axiom A Flow, Cascade, Geodesic Flow, SemiflowExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Flow." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Flow.html