RightDoubleBracketingBar
 Usage
 \[RightDoubleBracketingBar]
Notes
• Alias:  r||. • Matchfix operator. •  x  is by default interpreted as DoubleBracketingBar[x]. • Used in mathematics to indicate taking a norm. • Sometimes used for determinant. • Sometimes used to indicate a matrix. • Not the same as \[DoubleVerticalBar] . • Drawn in monospaced fonts with a small right-pointing tee to indicate direction. • Extensible character. • See Section 3.10.4. • See also: \[RightBracketingBar] .
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