Let \( V \) be an inner product space . Two vectors \( u, v \in V \) are called orthogonal if

\[ \langle u, v\rangle=0. \]

If two vectors \(u,v\) are orthogonal, we write \(u\perp v\).

See also Link to heading

• Pythagorean theorem
• orthogonal complement
• orthonormal system
• orthonormal basis