Algebraic and Analytic Geometry
《Algebraic and Analytic Geometry》 · 第 120 页 · Section 2.6「The Dual Space」，定义段
Using the notation of Theorem 2.24, we call the ordered basis $\beta^*=\{f_1,\ldots,f_n\}$ of $V^*$ that satisfies $f_i(x_j)=\delta_{ij}$ for $1\le i,j\le n$ the dual basis of $\beta$.