Lemma124ForasymmetricnnmatrixAAispsdifandonlyifAB0forallpsdBProofOnedirectioniseasyifAisnotpsdthenthereexistsx2RnforwhichAxxxAx0ButxxxTJxF15 x119x552 xTf 3x117 ID: 341308
Lemma12.4.ForasymmetricnnmatrixA AispsdifandonlyifAB0forallpsdB.Proof.Onedirectioniseasy:ifAisnotpsd