TeXipedia

textbardbl

Represents a double vertical bar character commonly used in mathematical notation and text formatting.

Overview

Serves as a versatile typographical element across various mathematical and technical contexts, particularly in set theory, logic, and formal specifications.

  • Often used to denote parallel lines or absolute value in mathematics
  • Appears in formal logic as a separator or delimiter
  • Frequently employed in computer science notation and programming language documentation
  • Provides a more prominent alternative to single vertical bars when stronger visual separation is needed

Examples

Double vertical bar as a norm notation in mathematics

∥x∥=∥x∥\|x\| = \text{\textbardbl}x\text{\textbardbl} 
\|x\| = \text{\textbardbl}x\text{\textbardbl}

Double vertical bar used to denote parallel lines in geometry

L1 ∥L2L_1 \text{ \textbardbl } L_2 
L_1 \text{ \textbardbl } L_2

Double vertical bar as a separator in set notation

{x ∥x>0}\{x \text{ \textbardbl } x > 0\} 
\{x \text{ \textbardbl } x > 0\}