Publications

Publications listed in

1. Books

[1] On λ-Nonlinear Boundary Eigenvalue Problems; Mathematical Research Vol. 71, Akademie Verlag, Berlin 1993, 124 pp. (94i:34042) [785.34054]
[2] Spectral theory of block operator matrices and applications; Imperial College Press, London 2008, xxxii+264 pp.

2. Articles

[3] Asymptotic boundary conditions for expansion theorems for boundary eigenvalue problems of the form N(y) = λP(y) with λ-depending Boundary Conditions; ZAMM 73 (1993) 7/8, T769–T773
(1 237 866) [801.41026]
[4] Kamke problems. Properties of the eigenfunctions; Math. Nachr. 170 (1994), 251–275 (with A.A.Shkalikov)
(95j:34025) [813.34071]
[5] Kamke's problem – properties of the eigenfunctions; in: Systems and Networks: Mathematical Theory and Applications, Mathematical Research, Vol. 79, Akademie Verlag, Berlin 1994, 885–888 
[813.34072]
[6] On fundamental systems for differential equations of Kamke type; Math. Z. 219 (1995), 609–629
(96g:34031) [827.34004]
[7] Boundary eigenvalue problems of Orr–Sommerfeld type; ZAMM 75 (1995) SII, 417–420 (with A.A.Shkalikov)
[837.34084]
[8] Spectral analysis for linear pencils N - λP of ordinary differential operators; Math. Nachr. 179 (1996), 275–305 (with A.A. Shkalikov)
(97b:34091) [862.34058]
[9] A selfadjoint linear pencil Q - λP of ordinary differential operators; Methods Funct. Anal. Topology 2:1 (1996), 38–54 (with H. Langer, R. Mennicken)
(97f:47046)
[10] Nonselfadjoint spectral problems for linear pencils N - λP of ordinary differential operators with λ–linear boundary conditions: Completeness results; Integral Equations Operator Theory 26:2 (1996), 222–248
(97f:47047) [862.34057]
[11] Spectral properties of a compactly perturbed linear span of projections; Integral Equations Operator Theory 26:3 (1996), 353-366 (with H. Langer, V. Pivovarchik)
(97j:47008) [865.47009]
[12] Spectral properties of the Orr–Sommerfeld problem; Proc. Roy. Soc. Edinburgh A 127:6 (1997), 1245-1261 (with H. Langer)
(99e:34119) [897.34070]
[13] Spectral decomposition of some nonselfadjoint block operator matrices; J. Operator Theory 39:2 (1998), 339-359 (with H. Langer)
(99d:47004)
[14] Lyapunov stability of a perturbed multiplication operator; in: Contributions to Operator Theory in Spaces with an Indefinite Metric, Operator Theory: Adv. Appl. 106 (1998), 309–326 (with S. Naboko)
[990.05639] (pdf version)
[15] On buckling problems; ZAMM 80 (2000), 633-639
[16] Nonclassical boundary eigenvalue problems: Linearization, spectral properties and applications; Habilitationsschrift, Regensburg 1998, 110 S.
[17] A linearization for a class of λ-nonlinear boundary eigenvalue problems; J. Math. Anal. Appl. 247 (2000), 331–355.
[18] Linear Operator Pencils with discrete spectrum; Integral Equations Operator Theory 37:3 (2000).
[19] Spectral problems for systems of differential equations y' + A0 y = λA1 y with λ–polynomial boundary conditions; Math. Nachr. 214 (2000), 129–172.
[20] Spectral issues for block operator matrices; in: R. Weikard, G. Weinstein (Eds.), Differential Equations and Mathematical Physics, AMS/IP Studies in Advanced Mathematics 16 (2000), 407–423
[21] Diagonalization of certain block operator matrices and applications to Dirac operators; Operator Theory: Adv. Appl. 122 (2001), 331–358 (with H. Langer)
[22] Corners of numerical ranges; Operator Theory: Adv. Appl. 124 (2001), 385-400 (with H. Langer, A. Markus)
[23] Boundary eigenvalue problems for differential equations N η = λPη with λ–polynomial boundary conditions; J. Differential Equations 170:2 (2001), 408–471
[24] Existence and Uniqueness of Contractive Solutions of some Riccati Equations; J. Funct. Anal. 179:2 (2001), 448–473 (with V. Adamjan, H. Langer)
[25] A new concept for block operator matrices: The quadratic numerical range; Linear Algebra Appl. 330 (2001), 89–112 (with H. Langer, A. Markus, V. Matsaev)
[26] Direct and inverse spectral problem for a system of differential equations depending rationally on the spectral parameter; Duke Math. J. 109:3 (2001), 413–449 (with R. Mennicken, A.L. Sakhnovich)
[27] Essential spectrum of a system of singular differential operators; Proc. Amer. Math. Soc. 130:6 (2002), 1699–1710 (with R. Mennicken, S. Naboko)
[28] The spectrum of the multiplication operator associated with a family of operators; J. London Math. Soc. 65:2 (2002), 483–492 (with R. Denk, M. Möller)
[29] Singular Dirac systems and Sturm-Liouville problems nonlinear in the spectral parameter; J. Differential Equations 181:2 (2002), 511–542 (with H. Schmid)
[30] On a class of non-self-adjoint quadratic matrix operator pencils arising in elasticity theory; J. Operator Theory 47:2 (2002), 325-341 (with V. Adamjan, V. Pivovarchik)
[31] Variational principles for eigenvalues of block operator matrices; Indiana Univ. Math. J. 51:6 (2002), 1427–1459 (with H. Langer, M. Langer)
[32] The block numerical range of an n × n block operator matrix; SIAM J. Matrix Anal. Appl. 24:4 (2003), 1003-1017 (with M. Wagenhofer)
[33] Self-adjoint block operator matrices with non-separated diagonal entries and their Schur complements; J. Funct. Anal. 199:2 (2003), 427-451 (with H. Langer, A. Markus, V. Matsaev)
[34] Eigenvalue bounds for the singular Sturm-Liouville problem with a complex potential; J. Phys. A: Math. Gen 36:13 (2003), 3773-3787 (with B.M. Brown, M. Langer, M. Marletta, M. Wagenhofer)
[35] Asymptotic separation of the spectrum of quadratic operator pencils associated with damped dynamical systems; Asymptot. Anal. 36:1 (2003), 1-12 (with V. Pivovarchik)
[36] A new method for eigenvalue estimates for Dirac operators on certain manifolds with Sk-symmetry; Differential Geom. Appl. 19:1 (2003), 1-14 (with M. Kraus)
[37] Pencils of differential operators containing the eigenvalue parameter in the boundary conditions; Proc. Roy. Soc. Edinburgh Sect. A 133:4 (2003), 893-917 (with M. Marletta, A.A. Shkalikov)
[38] Variational principles and eigenvalue estimates for unbounded block operator matrices and applications; J. Comp. Appl. Math. 171 (2004), 311-334 (with M. Kraus, M. Langer)
[39] Complete second order linear differential operator equations in Hilbert space and applications in hydrodynamics; Trans. Amer. Math. Soc. 356:12 (2004), 4737-4766 (with N. Kopachevsky, Ju. Pashkova, R. Mennicken)
[40] Eigenvalue accumulation for Dirac operators with spherically symmetric potential; J. Phys. A 37:36 (2004), 8657-8674 (with H. Schmid)
[41] A Krein space approach to PT-symmetry; Czechoslovak J. Phys. 54:10 (2004), 1113-1120 (with H. Langer)
[42] Spectrum of definite type of self-adjoint operators in Krein spaces; Linear Multilinear Algebra 53:2 (2005), 115-136 (with H. Langer, M. Langer, A. Markus)
[43] Spectral theory of the Klein-Gordon equation in Pontryagin spaces; Comm. Math. Phys. 267:1 (2006), 159-180 (with H. Langer, B. Najman)
[44] The spectrum of the multiplication operator associated with a family of operators in a Banach space; Oper. Theory Adv. Appl. 162 (2006), 103-116 (with R. Denk, M. Möller)
[45] Corrigendum to: "A Krein space approach to PT symmetry" [Czechoslovak J. Phys. 54:10 (2004), no. 10, 1113-1120]; Czechoslovak J. Phys. 56:9 (2006), 1063-1064 (with H. Langer)
[46] Variational principles for eigenvalues of the Klein-Gordon equation; J. Math. Phys. 47:10 (2006), 103506, 18 pp. (with M. Langer)
[47] Essential spectra of coupled systems of differential equations and applications in hydrodynamics; J. Differential Equations 243:1 (2007), 36-69 (with M. Marletta)
[48] The Virozub-Matsaev condition and spectrum of definite type for self-adjoint operator functions; Complex Anal. Oper. Theory 2:1 (2008), 99-134 (with H. Langer, M. Langer, M. Alexander)
[49] Spectral theory of the Klein-Gordon equation in Krein spaces; Proc. Edinb. Math. Soc. (2) 51:3 (2008), 711-750 (with H. Langer, N. Branko)

3. Editorial Work

[50] Differential and Integral Operators; Operator Theory: Adv. Appl. Vol. 102, Birkhäuser Verlag, Basel 1998, 324 S.
(with I.C. Gohberg, R. Mennicken)
(99d:47001)) [883.00019]
[51] Recent Progress in Operator Theory; Operator Theory: Adv. Appl. Vol. 103, Birkhäuser Verlag, Basel 1998, 283 S.
(with I.C. Gohberg, R. Mennicken)
(99d:47002) [883.00020]