These are the example-definitions with the problems I had most trouble with understanding during the lessons, some of them were pretty confusing to me. But hopefully, these will come in handy to determine what the question is asking.

When ,recently, preparing for an exam or a hot topic presentation I tend not to keep these right on my cheat sheet. And it has been very successful in term of understanding the problem as well as explaining to the professor how did I get the correct answer.