# vertical bar

## English

### Noun

vertical bar (plural vertical bars)

1. (computing) The ASCII character at the decimal position of 124, depicted as | or ¦;
2. (mathematics) represents an absolute value (e.g.  $|x|$)
3. (mathematics) norms (e.g. $||(x_1,x_2)||$)
• 2002, S. Long et al., A Meshless Local Petrov-Galerkin Method for Solving the Bending Problem of a Thin Plate, Tech Science Press
For the purpose of error estimation and convergence studies, the deflection and energy norm, ||w|| and ||e||, are calculated [...]
4. (mathematics) set definitions (e.g. $\{x|x<2\}$)
• 2006, K. Chung et al., Bifurcation analysis of a two-degree-of-freedom aeroelastic system with freeplay structural nonlinearity by a perturbation-incremental method, Journal of Sound and Vibration.
According to the three linear branches of the bilinear function for a freeplay model, the phase space $X \in R^8$ can be divided into three regions, $R_i (i = 1,2,3 )$, where each corresponds to a linear system:
$X' = AX + F_1$ in $R_1 = \{X \in R^8|x_1 < \alpha_f \}$
5. (mathematics) conditional probability (e.g. $P(X|Y)$)
6. (mathematics) divisibility (e.g. $a | b$)
7. (computing) a symbol which, in Unix, is used as a pipe
8. (computing) a symbol which, in regular expressions, indicates an alternation