The Wikipedia page https://en.wikipedia.org/wiki/Kripke_structure_(model_checking)#Example has an example of a Kripke structure $M = (S,R,L)$; however, others define Kripke structures as $M = (S,R,V)$ where $V$ is called the valuation.
What is the difference between these two definitions?
They seem to be symmetric, so it might not make a difference, but I want to understand the difference.