Introduction to Mathematical Logic, Sixth Edition
《Introduction to Mathematical Logic, Sixth Edition》 · 印刷第 481 页 Section 11.1.2「Subgroups and Homomorphisms」的复线性代数群约定、第 494 页 Section 11.2.2「Unipotent Radical」，Lemma 11.2.4 前的定义（省略中间内容）
Let $G\subset\mathrm{GL}(n,\mathbb C)$ be a linear algebraic group. […] For any linear algebraic group $G$ we set $\mathrm{Rad}_u(G)=\bigcup_{U\subset G}U$ ($U$ normal unipotent subgroup) and call $\mathrm{Rad}_u(G)$ the unipotent radical of $G$.