Orthogonal Group Definition Characterisation of Finite Extensions Algebra Annihilators Are Ideals Algebra Eigenbasis Criterion for Diagonal Matrix Representations Algebra Fixed Points of Mobius Maps Group Theory Cayley Hamilton Theorem Linear Algebra Characterizations of Normal Subgroups Algebra Nonnegative Linear Combinations Preserve Convexity Algebra Modules over Noetherian Rings Algebra Algebra Area