In math, we write a set using curly braces containing its elements. For example, a set typically appears in an expression like this:
In plain langauge, this represents the set containing the elements , , and .
An empty set, also called the null set, is respresented as a zero with a diagonal line through it or as an empty pair of curly braces.
A proper subset is denoted by the symbol ⊂
A proper superset is denoted by the superset symbol which looks like a U rotated ninety degrees to the left.
The subset operator is denoted using a U shapes symbol rotated ninety degrees to the righ with a horizontal line underneath.
The superset operator in set theory is denoted using the superset symbol which looks like a U turned ninety degrees counter clockwise with a horizontal line underneath.