If H11 is singular, we can still define the generalized Schur complement, using the Moore–Penrose inverse instead of .
The formula does not hold if H11 is singular. However, a generalization has been proven in 1974 by Carlson, Haynsworth and Markham,[4] to the effect that and .
Carlson, Haynsworth and Markham also gave sufficient and necessary conditions for equality to hold.
^Haynsworth, E. V., "Determination of the inertia of a partitioned Hermitian matrix", Linear Algebra and its Applications, volume 1 (1968), pages 73–81
^Zhang, Fuzhen (2005). The Schur Complement and Its Applications. Springer. p. 15. ISBN0-387-24271-6.
^The Schur Complement and Its Applications, p. 15, at Google Books
^Carlson, D.; Haynsworth, E. V.; Markham, T. (1974). "A generalization of the Schur complement by means of the Moore–Penrose inverse". SIAM J. Appl. Math. 16 (1): 169–175. doi:10.1137/0126013.
December 07, 2023
haynsworth, inertia, additivity, formula, mathematics, discovered, emilie, virginia, haynsworth, 1916, 1985, concerns, number, positive, negative, zero, eigenvalues, hermitian, matrix, block, matrices, into, which, partitioned, inertia, hermitian, matrix, defi. In mathematics the Haynsworth inertia additivity formula discovered by Emilie Virginia Haynsworth 1916 1985 concerns the number of positive negative and zero eigenvalues of a Hermitian matrix and of block matrices into which it is partitioned 1 The inertia of a Hermitian matrix H is defined as the ordered triple I n H p H n H d H displaystyle mathrm In H left pi H nu H delta H right whose components are respectively the numbers of positive negative and zero eigenvalues of H Haynsworth considered a partitioned Hermitian matrix H H 11 H 12 H 12 H 22 displaystyle H begin bmatrix H 11 amp H 12 H 12 ast amp H 22 end bmatrix where H11 is nonsingular and H12 is the conjugate transpose of H12 The formula states 2 3 I n H 11 H 12 H 12 H 22 I n H 11 I n H H 11 displaystyle mathrm In begin bmatrix H 11 amp H 12 H 12 ast amp H 22 end bmatrix mathrm In H 11 mathrm In H H 11 where H H11 is the Schur complement of H11 in H H H 11 H 22 H 12 H 11 1 H 12 displaystyle H H 11 H 22 H 12 ast H 11 1 H 12 Generalization editIf H11 is singular we can still define the generalized Schur complement using the Moore Penrose inverse H 11 displaystyle H 11 nbsp instead of H 11 1 displaystyle H 11 1 nbsp The formula does not hold if H11 is singular However a generalization has been proven in 1974 by Carlson Haynsworth and Markham 4 to the effect that p H p H 11 p H H 11 displaystyle pi H geq pi H 11 pi H H 11 nbsp and n H n H 11 n H H 11 displaystyle nu H geq nu H 11 nu H H 11 nbsp Carlson Haynsworth and Markham also gave sufficient and necessary conditions for equality to hold See also editBlock matrix pseudoinverse Sylvester s law of inertiaNotes and references edit Haynsworth E V Determination of the inertia of a partitioned Hermitian matrix Linear Algebra and its Applications volume 1 1968 pages 73 81 Zhang Fuzhen 2005 The Schur Complement and Its Applications Springer p 15 ISBN 0 387 24271 6 The Schur Complement and Its Applications p 15 at Google Books Carlson D Haynsworth E V Markham T 1974 A generalization of the Schur complement by means of the Moore Penrose inverse SIAM J Appl Math 16 1 169 175 doi 10 1137 0126013 Retrieved from https en wikipedia org w index php title Haynsworth inertia additivity formula amp oldid 1131762187, wikipedia, wiki, book, books, library,