I am currently reading a paper on verifiable delay functions and when talking about the security of Pietrzak's succinct argument the description of a group is mentioned:
Let $\operatorname{GGen}(\lambda)$ be a randomized algorithm that outputs the description of a group $\mathbb{G}$ of unknown order.
What does it mean by "description of a group"? (I know what "a group" is, I just do not understand the output of this function $\operatorname{GGen}(\lambda)$.)
Here is the paper: Page 5 chapter 3.1 http://crypto.stanford.edu/~dabo/papers/VDFsurvey.pdf