What it means
The set with nothing in it. Two sets whose intersection is empty are called disjoint.
Read aloud in real formulas
A ∩ B = ∅
Aethel says
A intersection B equals the empty set
A and B are disjoint
Typing it
- LaTeX
- \emptyset, \varnothing
- Unicode
- U+2205
Questions
How do you say ∅ out loud?
It is usually read “the empty set”.
What does ∅ mean in maths?
The set with nothing in it. Two sets whose intersection is empty are called disjoint.
How do you type ∅?
In LaTeX, write \emptyset, \varnothing. Its Unicode code point is U+2205.
What is ∅ often confused with?
It is easy to mistake for the Greek letter φ and the Scandinavian letter Ø.