Sets

A set is a well

A set is a well-defined collection of objects. Membership is shown by the symbol ∈, and non-membership by ∉. Sets are denoted by capital letters and e

Roster form lists all elements inside

Roster form lists all elements inside braces. Order does not matter and repetition is avoided. Set-builder form describes elements by a common propert

Important types include empty set

Important types include empty set, finite set, infinite set, singleton set, equal sets, and equivalent sets. The empty set has no elements, a singleto

A set A is a subset

A set A is a subset of B if every element of A belongs to B. A is a proper subset of B if A is a subset of B and A is not equal to B. The empty set is

Open

Open, closed, and half-open intervals describe subsets of R. The real line is R = (-∞, ∞). The length of (a,b), [a,b], [a,b), and (a,b] is b-a.