Let $F(x,u,Du,D^2u)=0$ for $x\in\Omega$ be our equation of interest. One way of defining a viscosity subsolution is this: We say $u$ is a viscosity subsolution iff for any test function $\phi\in C^2(\Omega)$ such that $u-\phi$ has a LOCAL maximum at $x_0$ then $F(x_0,D\phi(x_0),D^2\phi(x_0))\leq 0$. However in this paper http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.52.8750&rep=rep1&type=pdf the author replace the word local with GLOBAL. I believe this is fairly common in optimal control/stopping literature. Does this weaken the notion of viscosity solution or are they the same? I get the feeling they are still equivalent, but how?