p-Group Has Nontrivial Center Group Theory Simplicity Criterion for Semisimple Lie Algebras via Root Systems Algebra $\operatorname{SO}(3) \cong \mathrm{PSU}(2)$ — Proof Sketch Representation Theory Enough Injectives in the Category of Modules Algebra Cayley's Theorem Group Theory Cartan Subalgebras of Semisimple Lie Algebras over Algebraically Closed Fields Are Abelian Algebra Existence of Algebraic Closures Algebra Count of Irreducibles of a Finite Abelian Group Representation Theory Algebra Area