Introduction to Lie Algebras and Representation Theory
《Introduction to Lie Algebras and Representation Theory》 · 第 67 页 · Section 13「Abstract theory of weights」的根系约定及 Section 13.1「Weights」（省略习题引用、根格及其说明）；同义词形 `dominant integral linear function` 另见第 112 页 Section 21.1 的对应说明
Let $\Phi$ be a root system in a euclidean space $E$, with Weyl group $\mathcal W$. […] Let $\Lambda$ be the set of all $\lambda\in E$ for which $\langle\lambda,\alpha\rangle\in\mathbb Z$ $(\alpha\in\Phi)$, and call its elements weights. Since $\langle\lambda,\alpha\rangle=\frac{2(\lambda,\alpha)}{(\alpha,\alpha)}$ depends linearly on $\lambda$, $\Lambda$ is a subgroup of $E$ including $\Phi$. […] Fix a base $\Delta\subset\Phi$, and define $\lambda\in\Lambda$ to be dominant if all the integers $\langle\lambda,\alpha\rangle$ $(\alpha\in\Delta)$ are nonnegative, strongly dominant if these integers are positive.