Sets

Sets are a basic concept in Math, which means that there are no other primitive words to describe them. For example, if one asks: “What are sets?”, and you answer: “…a collection of elements.”, then the next question would be: “…well, what are collections then?”, and you can go on like this until you get a “circular logic” of explaining it. Therefore, consider sets as a fundamental concept in Math with which you can understand, build and explain more advanced concepts.

Notation

Set membership is denoted by the in operator $\in$. For example, if we want to say that number 2 is a member of natural numbers we write: $2 \in N$