Finite Extensions Are Algebraic Algebra Finite Generation of Zero Relations Algebra Injective Module Criterion via Exactness of Contravariant Hom Algebra Galois Criterion via Fixed Fields Algebra Concyclic Iff Real Cross-Ratio Group Theory Idempotent Endomorphisms Split Modules Algebra Functorial Properties of Tensor Products Algebra Algebra Tensor Product Is Well-Defined Algebra Algebra Area