Direct Sums: Abelian GroupsExplores the concept of direct sums in abelian groups, emphasizing the universal property and homomorphisms.
Group Algebra: Maschke's TheoremExplores Wedderburn's theorem, group algebras, and Maschke's theorem in the context of finite dimensional simple algebras and their endomorphisms.
Direct Sums: Lemme 1.2Delves into direct sums of abelian groups, showcasing their coproduct properties and universal verification.
Direct Sums ArithmeticExplores the arithmetic of direct sums in group theory, discussing conditions for equality.
Direct Sum of SubgroupsExplores the direct sum of subgroups in an abelian group and introduces the coproduct concept in Abelian categories.
