Alexander Markus

2017

On the norm of linear combinations of projections and some characterizations of Hilbert spaces

Krupnik, N. & Markus, A., 1 Jan 2017, Operator Theory: Advances and Applications. Springer International Publishing, p. 501-510 10 p. (Operator Theory: Advances and Applications; vol. 259).

Research output: Chapter in Book/Report/Conference proceeding › Chapter › peer-review

2012

Linearization, factorization, and the spectral compression of a self-adjoint analytic operator function under the condition (VM)

Langer, H., Markus, A. & Matsaev, V., 1 Jan 2012, A Panorama of Modern Operator Theory and Related Topics: The Israel Gohberg Memorial Volume. Dym , H., Kaashoek, M. A., Lancaster , P., Langer , H. & Lerer , L. (eds.). Springer Basel, p. 445-463 19 p.

Research output: Chapter in Book/Report/Conference proceeding › Chapter › peer-review

2 Scopus citations

2011

Connectedness of some fibres on a compact connected Lie group

Markus, A. & Tam, T. Y., 1 Oct 2011, In: Linear and Multilinear Algebra. 59, 10, p. 1121-1126 6 p.

Research output: Contribution to journal › Article › peer-review

2010

Convexity of ranges and connectedness of level sets of quadratic forms

Feldman, I., Krupnik, N. & Markus, A., 1 Jan 2010, Characteristic Functions, Scattering Functions and Transfer Functions. Alpay, D. & Vinnikov, V. (eds.). Springer International Publishing, p. 149-179 31 p. (Operator Theory: Advances and Applications; vol. 197).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

1 Scopus citations

2009

Self-adjoint analytic operator functions: Local spectral function and inner linearization

Langer, H., Markus, A. & Matsaev, V., 1 Apr 2009, In: Integral Equations and Operator Theory. 63, 4, p. 533-545 13 p.

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

2008

On operator algebras determined by a sequence of operator norms

Feintuch, A. & Markus, A., 1 Sep 2008, In: Journal of Operator Theory. 60, 2, p. 317-341 25 p.

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

The Virozub-Matsaev condition and spectrum of definite type for self-adjoint operator functions

Langer, H., Langer, M., Markus, A. & Tretter, C., 1 Mar 2008, In: Complex Analysis and Operator Theory. 2, 1, p. 99-134 36 p.

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

2006

Self-adjoint analytic operator functions and their local spectral function

Langer, H., Markus, A. & Matsaev, V., 1 Jun 2006, In: Journal of Functional Analysis. 235, 1, p. 193-225 33 p.

Research output: Contribution to journal › Article › peer-review

Open Access

9 Scopus citations

2005

A general time-varying estimation and control problem

Feintuch, A. & Markus, A., 1 Aug 2005, In: Mathematics of Control, Signals, and Systems. 17, 3, p. 217-230 14 p.

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Spectrum of definite type of self-adjoint operators in Krein spaces

Langer, H., Langer, M., Markus, A. & Tretter, C., 1 Mar 2005, In: Linear and Multilinear Algebra. 53, 2, p. 115-136 22 p.

Research output: Contribution to journal › Article › peer-review

11 Scopus citations

2004

Joint zero sets and ranges of several Hermitian forms over complex and quaternionic scalars

Binding, P. & Markus, A., 1 Jul 2004, In: Linear Algebra and Its Applications. 385, 1-3, p. 63-72 10 p.

Research output: Contribution to journal › Article › peer-review

Open Access

2 Scopus citations

Linear Algebra and Its Applications: Preface

Bart, H., Koltracht, I., Markus, A. & Rodman, L., 1 Jul 2004, In: Linear Algebra and Its Applications. 385, 1-3, p. 1-6 6 p.

Research output: Contribution to journal › Editorial

Open Access

Perturbation theory for analytic matrix functions: The semisimple case

Lancaster, P., Markus, A. S. & Zhou, F., 26 Jul 2004, In: SIAM Journal on Matrix Analysis and Applications. 25, 3, p. 606-626 21 p.

Research output: Contribution to journal › Article › peer-review

48 Scopus citations

2003

A wider class of stable gyroscopic systems

Lancaster, P., Markus, A. S. & Zhou, F., 1 Sep 2003, In: Linear Algebra and Its Applications. 370, SUPP, p. 257-267 11 p.

Research output: Contribution to journal › Article › peer-review

Open Access

11 Scopus citations

Self-adjoint block operator matrices with non-separated diagonal entries and their Schur complements

Langer, H., Markus, A., Matsaev, V. & Tretter, C., 20 Apr 2003, In: Journal of Functional Analysis. 199, 2, p. 427-451 25 p.

Research output: Contribution to journal › Article › peer-review

Open Access

20 Scopus citations

2002

On n-fold expansions for ordinary differential operators

Faierman, M., Markus, A., Matsaev, V. & Möller, M., 23 Aug 2002, In: Mathematische Nachrichten. 238, p. 62-77 16 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Repeated eigenvectors and the numerical range of self-adjoint quadratic operator polynomials

Lancaster, P., Markus, A. S. & Psarrakos, P., 3 Dec 2002, In: Integral Equations and Operator Theory. 44, 2, p. 243-253 11 p.

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

Similarity invariant subspaces and lie ideals in operator algebras

Belitskii, G. & Markus, A., 3 Dec 2002, In: Integral Equations and Operator Theory. 44, 2, p. 127-137 11 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

2001

A new concept for block operator matrices:The quadratic numerical range

Langer, H., Markus, A., Matsaev, V. & Tretter, C., 15 Jun 2001, In: Linear Algebra and Its Applications. 330, 1-3, p. 89-112 24 p.

Research output: Contribution to journal › Article › peer-review

Open Access

57 Scopus citations

1999

The Toeplitz-Hausdorff theorem and robust stability theory

Feintuch, A. & Markus, A., 1 Jan 1999, In: Mathematical Intelligencer. 21, 3, p. 33-37 5 p.

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

1998

On some properties of factorization indices

Feldman, I. & Markus, A., 1 Jan 1998, In: Integral Equations and Operator Theory. 30, 3, p. 326-337 12 p.

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

1997

Connectivity of level sets of quadratic forms and Hausdorff-Toeplitz type theorems

Lyubich, Y. & Markus, A., 1 Jan 1997, In: Positivity. 1, 3, p. 239-254 16 p.

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Locally definite operators in indefinite inner product spaces

Langer, H., Markus, A. & Matsaev, V., 1 Jan 1997, In: Mathematische Annalen. 308, 3, p. 405-424 20 p.

Research output: Contribution to journal › Article › peer-review

44 Scopus citations

Some results on numerical ranges and factorizations of matrix polynomials

Markus, A. S. & Rodman, L., 1 Jan 1997, In: Linear and Multilinear Algebra. 42, 2, p. 169-185 17 p.

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

The order of neutrality for linear operators on inner product spaces

Lancaster, P., Markus, A. S. & Zizler, P., 1 Jul 1997, In: Linear Algebra and Its Applications. 259, 1-3, p. 25-29 5 p.

Research output: Contribution to journal › Article › peer-review

Open Access

7 Scopus citations

1996

Factorization of selfadjoint operator polynomials

Lancaster, P., Markus, A. & Matsaev, V., 1 Dec 1996, In: Journal of Operator Theory. 35, 2, p. 337-348 12 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Isometric Dilations in Nest Algebras

Feintuch, A. & Markus, A., 1 Jan 1996, In: Integral Equations and Operator Theory. 26, 3, p. 346-352 7 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

The lossless embedding problem for time-varying contractive systems

Feintuch, A. & Markus, A., 19 Aug 1996, In: Systems and Control Letters. 28, 4, p. 181-187 7 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

1995

Definitizable operators and quasihyperbolic operator polynomials

Lancaster, P., Markus, A. S. & Matsaev, V. I., 1 Jan 1995, In: Journal of Functional Analysis. 131, 1, p. 1-28 28 p.

Research output: Contribution to journal › Article › peer-review

Open Access

28 Scopus citations

Factorization of Selfadjoint Quadratic Matrix Polynomials with Real Spectrum

Krupnik, I., Markus, A. & Lancaster, P., 1 Aug 1995, In: Linear and Multilinear Algebra. 39, 3, p. 263-272 10 p.

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Perturbations of isolated part of definite spectrum for G-selfadjoint operators and selfadjoint operator polynomials

Feldman, I., Markus, A. & Matsaev, V., 1 Dec 1995, In: Integral Equations and Operator Theory. 23, 4, p. 435-440 6 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Some remarks on factorization of selfadjoint matrix functions

Krupnik, I. & Markus, A., 1 Mar 1995, In: Integral Equations and Operator Theory. 21, 1, p. 71-76 6 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

1994

Low rank perturbations of strongly definitizable transformations and matrix polynomials

Lancaster, P., Markus, A. S. & Ye, Q., 1 Jan 1994, In: Linear Algebra and Its Applications. 197-198, C, p. 3-29 27 p.

Research output: Contribution to journal › Article › peer-review

Open Access

14 Scopus citations

The failure of factorization of positive matrix functions on noncircular contours

Markus, A. & Matsaev, V., 1 Jan 1994, In: Linear Algebra and Its Applications. 208-209, C, p. 231-237 7 p.

Research output: Contribution to journal › Article › peer-review

Open Access

2 Scopus citations

1993

Complete controllability and spectrum assignment in infinite dimensional spaces

Markus, A. S. & Olshevsky, V. R., 1 Mar 1993, In: Integral Equations and Operator Theory. 17, 1, p. 107-122 16 p.

Research output: Contribution to journal › Article › peer-review

7 Scopus citations

Factorization of a selfadjoint nonanalytic operator function II. Single spectral zone

Markus, A. & Matsaev, V., 1 Dec 1993, In: Integral Equations and Operator Theory. 16, 4, p. 539-564 26 p.

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

Factorization of matrix functions and characteristic properties of the circle

Krupnik, I., Markus, A. & Matsaev, V., 1 Dec 1993, In: Integral Equations and Operator Theory. 17, 4, p. 554-566 13 p.

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

1991

On the norm of polynomials of two adjoint projections

Feldman, I., Krupnik, N. & Markus, A., 1 Jan 1991, In: Integral Equations and Operator Theory. 14, 1, p. 69-91 23 p.

Research output: Contribution to journal › Article › peer-review

25 Scopus citations

Principal part of resolvent and factorization of an increasing nonanalytic operator-function

Markus, A. & Matsaev, V., 1 Sep 1991, In: Integral Equations and Operator Theory. 14, 5, p. 716-746 31 p.

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

1989

Norm of a linear combination of projectors in Hilbert space

Krupnik, N. Y., Markus, A. S. & Fel'dman, I. A., 1 Oct 1989, In: Functional Analysis and its Applications. 23, 4, p. 327-329 3 p.

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

1988

On the basis property for a certain part of the eigenvectors and associated vectors of a selfadjoint operator pencil

Markus, A. S. & Matsaev, V. I., 28 Feb 1988, In: Mathematics of the USSR - Sbornik. 61, 2, p. 289-307 19 p.

Research output: Contribution to journal › Article › peer-review

14 Scopus citations

1987

Basis property of subsystems of eigen- and associated vectors of a self-adjoint operator pencil

Markus, A. S. & Matsaev, V. I., 1 Jan 1987, In: Functional Analysis and its Applications. 21, 1, p. 73-75 3 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

1985

A theorem on comparison of spectra, and the spectral asymptotics for a keldysh pencil

Markus, A. S. & Matsaev, V. I., 28 Feb 1985, In: Mathematics of the USSR - Sbornik. 51, 2, p. 389-404 16 p.

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

1983

The change of the Jordan structure of a mtrix under small perturbations

Markus, A. S. & Parilis, E. È., 1 Jan 1983, In: Linear Algebra and Its Applications. 54, C, p. 139-152 14 p.

Research output: Contribution to journal › Article › peer-review

Open Access

32 Scopus citations

1979

Asymptotic behavior of spectra of operators which are close to normal

Markus, A. S. & Matsaev, V. I., 1 Jul 1979, In: Functional Analysis and its Applications. 13, 3, p. 233-235 3 p.

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

1978

Operators which weakly perturb the spectrum

Markus, A. S. & Sementsul, A. A., 1 May 1978, In: Siberian Mathematical Journal. 19, 3, p. 455-460 6 p.

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

1977

Index of an operator matrix

Markus, A. S. & Fel'dman, I. A., 1 Apr 1977, In: Functional Analysis and its Applications. 11, 2, p. 149-151 3 p.

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

1976

Factorization of a weakly hyperbolic bundle

Markus, A. S. & Matsaev, V. I., 1 Jan 1976, In: Functional Analysis and its Applications. 10, 1, p. 69-71 3 p.

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

1975

Spectral theory of holomorphic operator-functions in Hilbert space

Markus, A. S. & Matsaev, V. I., 1 Jan 1975, In: Functional Analysis and its Applications. 9, 1, p. 73-74 2 p.

Research output: Contribution to journal › Article › peer-review

18 Scopus citations

1974

Unitary spectrum of a contraction in Banach space

Markus, A. S., Nikol'skaya, L. N. & Nikol'skii, N. K., 1 Mar 1974, In: Journal of Soviet Mathematics. 2, 2, p. 112-119 8 p.

Research output: Contribution to journal › Article › peer-review

Open Access

1 Scopus citations

Alexander Markus

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