What is a set notation? Please explain what it is and give examples as well please. It would help a lot. Thank you.

Set notation is a mathematical notation used to describe a set, which is a collection of distinct objects. It provides a concise and standardized way to represent sets in mathematical texts and discussions. In set notation, sets are typically represented by listing their elements or defining properties that the elements must satisfy.

There are several commonly used symbols and notations in set notation:

1. Enumeration notation: Sets can be defined by listing their elements inside curly braces '{ }'. For example:
- A = {1, 2, 3} represents a set A containing the elements 1, 2, and 3.
- B = {a, b, c, d} represents a set B containing the elements 'a', 'b', 'c', and 'd'.

2. Set-builder notation: Sets can also be defined by specifying the properties that the elements must satisfy. It is written using the symbol '|' or ':' which means "such that".
- C = {x | x is an even number} represents a set C containing all even numbers. Here, the expression "x | x is an even number" defines the property that elements in the set must be even.
- D = {y : y > 0 and y < 5} represents a set D containing all numbers greater than 0 and less than 5.

3. Universal set notation: The universal set, which is the set containing all possible elements, is often denoted by the symbol 'U'.
- U = {1, 2, 3, 4, 5} represents a universal set U containing the integers from 1 to 5.

4. Empty set notation: The empty set, which contains no elements, is denoted by the symbol '∅' or '{}'.
- ∅ represents an empty set.

These notations help mathematicians and other researchers to describe sets clearly and precisely, allowing for effective communication and analysis of mathematical concepts.