Algebraic and Analytic Geometry
《Algebraic and Analytic Geometry》 · 第 341 页 · Section 6.2「Gram–Schmidt Orthogonalization Process and Orthogonal Complements」，定义段
Let $V$ be an inner product space. A subset of $V$ is an orthonormal basis for $V$ if it is an ordered basis that is orthonormal.