I'm trying to understand Minkwoski difference, as it relates to collision detection. 

It seems, to me, that there are two definitions of Minkowski difference floating around. One, as defined by [wikipedia](https://en.wikipedia.org/wiki/Minkowski_addition "Minkowski addition @ en.wikipedia.org") and the other as defined for example [here](http://twistedoakstudios.com/blog/Post554_minkowski-sums-and-differences "Minkowski sums and differences @ twisted oak studios.com/blog"). My question is, am I wrong? Are those two definitions equivalent? 

My intuition says no, because according to the Wikipedia definition, if `B` contains the origin then `B+c` contains `c`, and that means that every such `c` must be contained in `A`. However, according to the other definition, `A-B` might contain points not in `A`.