Naive Lie Theory
《Naive Lie Theory》 · 第 37 页 · Chapter 2，Section 2.5「Recovering a Group from Its Representations」
Recall (see 2.3.2 (3)) that a rational representation of $G$ is a finite dimensional vector space $V$ (called a $G$-module) together with a homomorphism of algebraic groups $r_V \colon G \to \mathrm{GL}(V)$. We denote by $1$ the trivial $G$-module: $1 = k$ and $r_1(g) = 1$ for all $g \in G$.