\overleftrightarrow{AB}The command \overleftrightarrow{AB} is used in LaTeX to place a double-headed arrow over the text 'AB'. This is often used in mathematical notation to denote a line segment or a vector that extends infinitely in both directions, passing through points A and B.
Denotes a line passing through points A and B, extending infinitely in both directions.
\overleftrightarrow{AB}Intersection of two lines, where line PQ and line RS intersect at point T.
\overleftrightarrow{PQ} \cap \overleftrightarrow{RS} = \{T\}Describing two parallel lines in geometric notation.
\text{The line } \overleftrightarrow{XY} \text{ is parallel to the line } \overleftrightarrow{MN}.