Vertical bar

A vertical bar is the glyph "|". It has several other names besides vertical bar, such as "pipe", "vertical slash", and "bar". In mathematics, it may be put on both sides of a real or complex number to mean its absolute value. When applied on both sides of a matrix, it means its determinant. When placed in between two numbers, it means the divisibility relation (for example. formula_1 means ""a" divides "b"").
In mathematics, double vertical bars are also used to refer to various mathematical concepts. These include the parallel relation (as in formula_2) and the norm of a vector (as in formula_3).