The \parallel function of LaTeX is a mathematical symbol used to represent the parallel relationship between two objects or lines. This command is often used in geometry or vector analysis to show that two lines or planes are parallel.

The command \parallel

First example:

$$a \parallel b$$

which gives

\[a \parallel b\]

Second example:

The lines $d_1$ and $d_2$ are parallel:

$$d_1 \parallel d_2$$
\[d_1 \parallel d_2\]