Intro to Set Theory

Set #

A well defined unordered collection of distinct elements is called a set.

Null Set / Empty Set #

A set with no elements. Denoted as {}=Φ

Subset #

If every element of B is also element of A then B⊆A. Every set is a subset of itself: A⊆A

Proper Subset #

Any subset of A which is not a trivial subset of A (itself) is called proper subset of A. B is a proper subset of A if B⊂A

Cardinality #

Total number of elements in a set.

Property #

If A⊆B and B⊆A ⇒ A=B