Hello Everyone.

While I was reading along in a book I came across this: It says the convex hull is

The are vectors in a vector space and the complex scalars. But from my understanding (and wikipedia verifies this) the definition of a convex hull requires . Normally I'd just think this was a typo, but the text goes on to use the fact that . So are the two things equivalent or what? I can't see how they are. (Crying). Help please!