I don't know if this is the correct site for this question. If not, if anyone has info on general math bulletin boards, it would be greatly appreciated. thanks!! I understand a relation is a set, and you can have an ordered pair, ie (V,E), where E is a binary relation on V. This of course is a graph. Functions are just a type of relation, with the added specifics that each element of a set S must correspond with another unique element in S or say another set T. Hence a function is also a set of these pairings, ie f:S->T. What are operations, though? Are these sets as well? Can they be described as a set. If I look closely at the definition, an operation C on sets, C:A->A is just like a function. Is an operation just a specialized function with the added requirement that the mapping be from set A to itself, ie closure? If this is the case, then, are all operations functions, and all functions relations?? Finally, does the general definition of operation require closure on the set??