Double Bar -- from Wolfram MathWorld
- ️Weisstein, Eric W.
- ️Thu Dec 30 1999
The double bar symbol
is used to denote certain kinds of norms in mathematics
(e.g.,
or
). It is also used to denote parallel
lines, as in
,
and in an older notation for the covariant derivative.
In this work, the notation
or
is reserved for matrix and function
norms, respectively.
See also
Bar, Covariant Derivative, Norm, Matrix Norm, Parallel, Single Bar
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References
Bringhurst, R. The Elements of Typographic Style, 2nd ed. Point Roberts, WA: Hartley and Marks, p. 277, 1997.
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Cite this as:
Weisstein, Eric W. "Double Bar." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/DoubleBar.html