If set is closed under some operation, what does that tell us the about structure of the groupoid?
It's a question from one of the previous math exams which was shown to me by one of my friends.
Unfortunately, I can't find a good answer to it. As far as I know, the answer is nothing, because of the definition of groupoid we use. Here's what (among other things) my math textbook has to say about groupoids:
Ordered pair (S,*), where arbitrary binary operation closed in set S is marked with *, is called groupoid.