Def:Similarity Def:Diagonalizable Def:Multiplicity Thm:DiagMultiplicity Def:SchurFactorization Def:OrthDiag Def:Spectrum Thm:SpectralTheorem Def:SpectralDecomposition Def:QuadForm Thm:PrincipalAxesTheorem Def:PrincipalAxes Thm:ClassificationQuadForms Thm:EigensStretching Def:SingularValues Def:SVD Thm:SVD