What it means
Inside a probability, a vertical bar means "given": P(A | B) is the probability of A when B is known. In number theory a | b means a divides b. In set-builder notation it means "such that". A pair of bars around a quantity is an absolute value.
Read aloud in real formulas
P(A | B) = P(A ∩ B) / P(B)
Aethel says
P of A given B equals P of A intersection B, over P of B
conditional probability
{x | x > 0}
Aethel says
the set of x such that x is greater than 0
the set of x such that x is positive
Typing it
- LaTeX
- \mid, |
- Unicode
- U+007C, U+2223
Formulas that use it
Questions
How do you say | out loud?
It is usually read “given”, and also “divides” or “such that”.
What does | mean in maths?
Inside a probability, a vertical bar means "given": P(A | B) is the probability of A when B is known. In number theory a | b means a divides b. In set-builder notation it means "such that". A pair of bars around a quantity is an absolute value.
How do you type |?
In LaTeX, write \mid, |. Its Unicode code point is U+007C, U+2223.