Algebraic and Analytic Geometry
《Algebraic and Analytic Geometry》 · 第 8-9 页 · Section 1.2「Vector Spaces」
An $m\times n$ matrix with entries from a field $F$ is a rectangular array of the form $\begin{pmatrix}a_{11}&a_{12}&\cdots&a_{1n}\\a_{21}&a_{22}&\cdots&a_{2n}\\\vdots&&&\vdots\\a_{m1}&a_{m2}&\cdots&a_{mn}\end{pmatrix}$. … In this book, we denote matrices by capital italic letters (e.g., $A$, $B$, and $C$), and we denote the entry of a matrix $A$ that lies in row $i$ and column $j$ by $A_{ij}$.