What it means
The length or size of a vector or matrix. Without a subscript it usually means the ordinary Euclidean length; ‖x‖₁ adds the absolute values instead.
Read aloud in real formulas
‖x‖ = √(x₁² + x₂²)
Aethel says
the norm of x equals the square root of the quantity x sub one squared plus x sub two squared
the length of a vector in the plane
L = ‖y − Xβ‖²
Aethel says
L equals the norm of y minus X beta, squared
the squared error of a linear model
Typing it
- LaTeX
- \|x\|, \lVert x \rVert
- Unicode
- U+2016
Questions
How do you say ‖x‖ out loud?
It is usually read “the norm of x”.
What does ‖x‖ mean in maths?
The length or size of a vector or matrix. Without a subscript it usually means the ordinary Euclidean length; ‖x‖₁ adds the absolute values instead.
How do you type ‖x‖?
In LaTeX, write \|x\|, \lVert x \rVert. Its Unicode code point is U+2016.