LeftDoubleBracketingBar
 Usage
 \[LeftDoubleBracketingBar]
Notes
• Alias:  l||. • 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 left-pointing tee to indicate direction. • Extensible character. • See Section 3.10.4. • See also: \[LeftBracketingBar] .
| 
