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Indefinite Inner Product Spaces, Schur Analysis, and Differential Equations pp 3–16Cite as

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List of Publications* of Professor Dr. Dr. h.c. mult. Heinz Langer

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Part of the book series: Operator Theory: Advances and Applications ((LOLS,volume 263))

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References

  1. Christian Engström, Heinz Langer, and Christiane Tretter. Rational eigenvalue problems and applications to photonic crystals. J. Math. Anal. Appl., 445(1):240–279, 2017.

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  2. Vadim Adamyan, Heinz Langer, Christiane Tretter, and MonikaWinklmeier. Dirac-Krein systems on star graphs. Integral Equations Operator Theory, 86(1):121–150, 2016.

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  3. Heinz Langer. Transfer functions and local spectral uniqueness for Sturm–Liouville operators, canonical systems and strings. Integral Equations Operator Theory, 85(1):1–23, 2016.

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  4. Mark G. Krein and Heinz Langer. Continuation of Hermitian positive definite functions and related questions. Integral Equations Operator Theory, 78(1):1–69, 2014.

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  5. Orif O. Ibrogimov, Heinz Langer, Matthias Langer, and Christiane Tretter. Essential spectrum of systems of systems of singular differential equations. Acta Sci. Math. (Szeged), 79:423–465, 2013.

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  6. B. Malcolm Brown, Heinz Langer, and Matthias Langer. Bessel-type operators with an inner singularity. Integral Equations Operator Theory, 75(2):257–300, 2013.

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  7. Daniel Alpay, Aad Dijksma, Heinz Langer, and Dan Volok. A Schur transformation for functions in a general class of domains. Indag. Math. (N.S.), 23(4):921–969, 2012.

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  8. Charles Fulton, Heinz Langer, and Annemarie Luger. Mark Krein’s method of directing functionals and singular potentials. Math. Nachr., 285(14-15):1791–1798, 2012.

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  9. Fritz Gesztesy, Heinz Langer, Mark Malamud, and Reinhard Mennicken. Editorial [Special issue devoted to Eduard R. Tsekanovskiĭ on the occasion of his seventy-fifth birthday]. Math. Nachr., 285(14-15):1675–1676, 2012.

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  10. H. Langer, A. Markus, and V. Matsaev. Linearization, factorization, and the spectral compression of a self-adjoint analytic operator function under the condition (VM). In A panorama of modern operator theory and related topics, volume 218 of Oper. Theory Adv. Appl., pages 445–463. Birkhäuser/Springer Basel AG, Basel, 2012.

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  11. Heinz Langer, Annemarie Luger, and Vladimir Matsaev. Convergence of generalized Nevanlinna functions. Acta Sci. Math. (Szeged), 77(3-4):425–437, 2011.

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  12. C. Fulton and H. Langer. Sturm–Liouville operators with singularities and generalized Nevanlinna functions. Complex Anal. Oper. Theory, 4(2):179–243, 2010.

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  13. Uwe Günther, Heinz Langer, and Christiane Tretter. On the spectrum of the magnetohydrodynamic mean-field α2-dynamo operator. SIAM J. Math. Anal., 42(3):1413–1447, 2010.

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  14. Daniel Alpay, Aad Dijksma, Heinz Langer, Simeon Reich, and David Shoikhet. Boundary interpolation and rigidity for generalized Nevanlinna functions. Math. Nachr., 283(3):335–364, 2010.

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  15. D. Alpay, A. Dijksma, and H. Langer. Augmented Schur parameters for generalized Nevanlinna functions and approximations. In Spectral theory in inner product spaces and applications, volume 188 of Oper. Theory Adv. Appl., pages 1–30. Birkhäuser Verlag, Basel, 2009.

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  16. Heinz Langer. Speech on the occasion of the retirement of Peter Jonas. In Spectral theory in inner product spaces and applications, volume 188 of Oper. Theory Adv. Appl., pages xvii–xx. Birkhäuser Verlag, Basel, 2009.

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  17. D. Alpay, A. Dijksma, and H. Langer. The Schur transformation for Nevanlinna functions: operator representations, resolvent matrices, and orthogonal polynomials. In Modern analysis and applications. The Mark Krein Centenary Conference. Vol. 1: Operator theory and related topics, volume 190 of Oper. Theory Adv. Appl., pages 27–63. Birkhäuser Verlag, Basel, 2009.

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  18. Heinz Langer, Alexander Markus, and Vladimir Matsaev. Self-adjoint analytic operator functions: local spectral function and inner linearization. Integral Equations Operator Theory, 63(4):533–545, 2009.

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  19. Heinz Langer, Branko Najman, and Christiane Tretter. Spectral theory of the Klein–Gordon equation in Krein spaces. Proc. Edinb. Math. Soc. (2), 51(3):711–750, 2008.

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  20. Heinz Langer, Matthias Langer, Alexander Markus, and Christiane Tretter. The Virozub–Matsaev condition and spectrum of definite type for self-adjoint operator functions. Complex Anal. Oper. Theory, 2(1):99–134, 2008.

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  21. D. Alpay, R.W. Buursema, A. Dijksma, and H. Langer. The combined moment and interpolation problem for Nevanlinna functions. In Operator theory, structured matrices, and dilations, volume 7 of Theta Ser. Adv. Math., pages 1–28. Theta, Bucharest, 2007.

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  22. P. Jonas and H. Langer. On the spectrum of the self-adjoint extensions of a nonnegative linear relation of defect one in a Krein space. In Operator theory in inner product spaces, volume 175 of Oper. Theory Adv. Appl., pages 121–158. Birkhäuser, Basel, 2007.

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  23. D. Alpay, A. Dijksma, and H. Langer. The transformation of Issai Schur and related topics in an indefinite setting. In System theory, the Schur algorithm and multidimensional analysis, volume 176 of Oper. Theory Adv. Appl., pages 1–98. Birkhäuser, Basel, 2007.

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  24. Daniel Alpay, Aad Dijksma, Heinz Langer, and Yuri Shondin. The Schur transformation for generalized Nevanlinna functions: interpolation and self-adjoint operator realizations. Complex Anal. Oper. Theory, 1(2):169–210, 2007.

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  25. D. Alpay, A. Dijksma, and H. Langer. J Ɩ-unitary factorization and the Schur algorithm for Nevanlinna functions in an indefinite setting. Linear Algebra Appl., 419(2-3):675–709, 2006.

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  26. Heinz Langer and Christiane Tretter. Corrigendum to: “A Krein space approach to PT symmetry” [Czechoslovak J. Phys. 54 (2004), no. 10, 1113–1120. Czechoslovak J. Phys., 56(9):1063–1064, 2006.

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  27. Heinz Langer and Franciszek Hugon Szafraniec. Bounded normal operators in Pontryagin spaces. In Operator theory in Krein spaces and nonlinear eigenvalue problems, volume 162 of Oper. Theory Adv. Appl., pages 231–251. Birkhäuser, Basel, 2006.

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  28. Vadim Adamyan, Peter Jonas, and Heinz Langer. Partial non-stationary perturbation determinants for a class of J-symmetric operators. In Operator theory in Krein spaces and nonlinear eigenvalue problems, volume 162 of Oper. Theory Adv. Appl., pages 1–17. Birkhäuser, Basel, 2006.

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  29. Heinz Langer, Branko Najman, and Christiane Tretter. Spectral theory of the Klein–Gordon equation in Pontryagin spaces. Comm. Math. Phys., 267(1):159–180, 2006.

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  30. Daniel Alpay, Aad Dijksma, Heinz Langer, and Gerald Wanjala. Basic boundary interpolation for generalized Schur functions and factorization of rational J-unitary matrix functions. In Interpolation, Schur functions and moment problems, volume 165 of Oper. Theory Adv. Appl., pages 1–29. Birkhäuser, Basel, 2006.

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  31. Heinz Langer. Speech of Heinz Langer. In Operator theory and indefinite inner product spaces, volume 163 of Oper. Theory Adv. Appl., pages xvii–xix. Birkhäuser, Basel, 2006.

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  32. H. Langer, A. Markus, and V. Matsaev. Self-adjoint analytic operator functions and their local spectral function. J. Funct. Anal., 235(1):193–225, 2006.

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  33. A. Bátkai, P. Binding, A. Dijksma, R. Hryniv, and H. Langer. Spectral problems for operator matrices. Math. Nachr., 278(12-13):1408–1429, 2005.

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  34. Heinz Langer, Matthias Langer, Alexander Markus, and Christiane Tretter. Spectrum of definite type of self-adjoint operators in Krein spaces. Linear Multilinear Algebra, 53(2):115–136, 2005.

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  35. Heinz Langer and Christiane Tretter. A Krein space approach to PT-symmetry. Czechoslovak J. Phys., 54(10):1113–1120, 2004.

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  36. Aad Dijksma, Heinz Langer, Annemarie Luger, and Yuri Shondin. Minimal realizations of scalar generalized Nevanlinna functions related to their basic factorization. In Spectral methods for operators of mathematical physics, volume 154 of Oper. Theory Adv. Appl., pages 69–90. Birkhäuser, Basel, 2004.

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  37. Vadim Adamyan and Heinz Langer. Partial non-stationary perturbation determinants. In Spectral methods for operators of mathematical physics, volume 154 of Oper. Theory Adv. Appl., pages 1–18. Birkhäuser, Basel, 2004.

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  38. Heinz Langer, Matthias Langer, and Zoltán Sasvári. Continuations of Hermitian indefinite functions and corresponding canonical systems: an example. Methods Funct. Anal. Topology, 10(1):39–53, 2004.

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  39. D. Alpay, T.Ya. Azizov, A. Dijksma, H. Langer, and G. Wanjala. The Schur algorithm for generalized Schur functions. IV. Unitary realizations. In Current trends in operator theory and its applications, volume 149 of Oper. Theory Adv. Appl., pages 23–45. Birkhäuser, Basel, 2004.

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  40. P. Binding, H. Langer, and M. Möller. Oscillation results for Sturm–Liouville problems with an indefinite weight function. J. Comput. Appl. Math., 171(1-2):93–101, 2004.

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  41. D. Alpay, A. Dijksma, and H. Langer. Factorization of J-unitary matrix polynomials on the line and a Schur algorithm for generalized Nevanlinna functions. Linear Algebra Appl., 387:313–342, 2004.

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  42. Heinz Langer and Andreas Lasarow. Solution of a multiple Nevanlinna–Pick problem via orthogonal rational functions. J. Math. Anal. Appl., 293(2):605–632, 2004.

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  43. Aad Dijksma, Heinz Langer, and Yuri Shondin. Rank one perturbations at infinite coupling in Pontryagin spaces. J. Funct. Anal., 209(1):206–246, 2004.

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  44. Branko Ćurgus and Heinz Langer. Continuous embeddings, completions and complementation in Krein spaces. Rad. Mat., 12(1):37–79, 2003.

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  45. D. Alpay, T.Ya. Azizov, A. Dijksma, H. Langer, and G. Wanjala. A basic interpolation problem for generalized Schur functions and coisometric realizations. In Reproducing kernel spaces and applications, volume 143 of Oper. Theory Adv. Appl., pages 39–76. Birkhäuser, Basel, 2003.

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  46. Daniel Alpay, Tomas Azizov, Aad Dijksma, and Heinz Langer. The Schur algorithm for generalized Schur functions. III. J-unitary matrix polynomials on the circle. Linear Algebra Appl., 369:113–144, 2003.

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  47. H. Langer, A. Markus, V. Matsaev, and C. Tretter. Self-adjoint block operator matrices with non-separated diagonal entries and their Schur complements. J. Funct. Anal., 199(2):427–451, 2003.

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  48. D. Alpay, T.Ya. Azizov, A. Dijksma, and H. Langer. The Schur algorithm for generalized Schur functions. II. Jordan chains and transformations of characteristic functions. Monatsh. Math., 138(1):1–29, 2003.

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  49. David Eschwé and Heinz Langer. Triple variational principles for eigenvalues of self-adjoint operators and operator functions. SIAM J. Math. Anal., 34(1):228–238 (electronic), 2002.

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  50. Heinz Langer, Matthias Langer, and Christiane Tretter. Variational principles for eigenvalues of block operator matrices. Indiana Univ. Math. J., 51(6):1427–1459, 2002.

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  51. H. Langer, A.C.M. Ran, and B.A. van de Rotten. Invariant subspaces of infinite dimensional Hamiltonians and solutions of the corresponding Riccati equations. In Linear operators and matrices, volume 130 of Oper. Theory Adv. Appl., pages 235–254. Birkhäuser, Basel, 2002.

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  52. D. Alpay, A. Dijksma, and H. Langer. On the Loewner problem in the class N κ . Proc. Amer. Math. Soc., 130(7):2057–2066, 2002.

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  53. H. Langer, H.S.V. de Snoo, and V.A. Yavrian. A relation for the spectral shift function of two self-adjoint extensions. In Recent advances in operator theory and related topics (Szeged, 1999), volume 127 of Oper. Theory Adv. Appl., pages 437–445. Birkhäuser, Basel, 2001.

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  54. László Kérchy and Heinz Langer. Béla Szőkefalvi-Nagy 1913–1998. In Recent advances in operator theory and related topics (Szeged, 1999), volume 127 of Oper. Theory Adv. Appl., pages xxi–xxxviii. Birkhäuser, Basel, 2001.

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  55. Daniel Alpay, Tomas Azizov, Aad Dijksma, and Heinz Langer. The Schur algorithm for generalized Schur functions. I. Coisometric realizations. In Systems, approximation, singular integral operators, and related topics (Bordeaux, 2000), volume 129 of Oper. Theory Adv. Appl., pages 1–36. Birkhäuser, Basel, 2001.

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  56. Heinz Langer and Christiane Tretter. Diagonalization of certain block operator matrices and applications to Dirac operators. In Operator theory and analysis (Amsterdam, 1997), volume 122 of Oper. Theory Adv. Appl., pages 331–358. Birkhäuser, Basel, 2001.

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  57. P. Binding, R. Hryniv, H. Langer, and B. Najman. Elliptic eigenvalue problems with eigenparameter dependent boundary conditions. J. Differential Equations, 174(1):30–54, 2001.

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  58. Heinz Langer, Alexander Markus, and Christiane Tretter. Corners of numerical ranges. In Recent advances in operator theory (Groningen, 1998), volume 124 of Oper. Theory Adv. Appl., pages 385–400. Birkhäuser, Basel, 2001.

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  59. H. Langer, A.Markus, V. Matsaev, and C. Tretter. A new concept for block operator matrices: the quadratic numerical range. Linear Algebra Appl., 330(1-3):89–112, 2001.

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  60. Vadim Adamjan, Heinz Langer, and Matthias Langer. A spectral theory for a λ- rational Sturm–Liouville problem. J. Differential Equations, 171(2):315–345, 2001.

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  61. V. Adamjan, H. Langer, and M. Möller. Compact perturbation of definite type spectra of self-adjoint quadratic operator pencils. Integral Equations Operator Theory, 39(2):127–152, 2001.

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  62. Vadim Adamjan, Heinz Langer, and Christiane Tretter. Existence and uniqueness of contractive solutions of some Riccati equations. J. Funct. Anal., 179(2):448–473, 2001.

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  63. Bernhard Bodenstorfer, Aad Dijksma, and Heinz Langer. Dissipative eigenvalue problems for a Sturm–Liouville operator with a singular potential. Proc. Roy. Soc. Edinburgh Sect. A, 130(6):1237–1257, 2000.

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  64. Paul Binding, David Eschwé, and Heinz Langer. Variational principles for real eigenvalues of self-adjoint operator pencils. Integral Equations Operator Theory, 38(2):190–206, 2000.

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  65. Heinz Langer and Annemarie Luger. A class of 2 × 2-matrix functions. Glas. Mat. Ser. III, 35(55)(1):149–160, 2000. Dedicated to the memory of Branko Najman.

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  66. Daniel Alpay, Aad Dijksma, and Heinz Langer. Classical Nevanlinna–Pick interpolation with real interpolation points. In Operator theory and interpolation (Bloomington, IN, 1996), volume 115 of Oper. Theory Adv. Appl., pages 1–50. Birkhäuser, Basel, 2000.

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  67. H. Langer, A. Markus, and V. Matsaev. Linearization and compact perturbation of self-adjoint analytic operator functions. In Operator theory and related topics, Vol. II (Odessa, 1997), volume 118 of Oper. Theory Adv. Appl., pages 255–285. Birkhäuser, Basel, 2000.

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  68. Aad Dijksma, Heinz Langer, Yuri Shondin, and Chris Zeinstra. Self-adjoint operators with inner singularities and Pontryagin spaces. In Operator theory and related topics, Vol. II (Odessa, 1997), volume 118 of Oper. Theory Adv. Appl., pages 105–175. Birkhäuser, Basel, 2000.

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  69. Vadim Adamjan and Heinz Langer. The spectral shift function for certain block operator matrices. Math. Nachr., 211:5–24, 2000.

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  70. A. Dijksma, H. Langer, A. Luger, and Yu. Shondin. A factorization result for generalized Nevanlinna functions of the class N κ . Integral Equations Operator Theory, 36(1):121–125, 2000.

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  71. Branko Ćurgus, Aurelian Gheondea, and Heinz Langer. On singular critical points of positive operators in Krein spaces. Proc. Amer. Math. Soc., 128(9):2621–2626, 2000.

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  72. H. Langer and H. Woracek. Resolvents of symmetric operators and the degenerated Nevanlinna–Pick problem. In Recent progress in operator theory (Regensburg, 1995), volume 103 of Oper. Theory Adv. Appl., pages 233–261. Birkhäuser, Basel, 1998.

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  73. Heinz Langer and Henrik Winkler. Direct and inverse spectral problems for generalized strings. Integral Equations Operator Theory, 30(4):409–431, 1998. Dedicated to the memory of Mark Grigorievich Krein (1907–1989).

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  74. Heinz Langer and Christiane Tretter. Spectral decomposition of some nonselfadjoint block operator matrices. J. Operator Theory, 39(2):339–359, 1998.

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  75. Heinz Langer and Christiane Tretter. Spectral properties of the Orr–Sommerfeld problem. Proc. Roy. Soc. Edinburgh Sect. A, 127(6):1245–1261, 1997.

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  76. Aad Dijksma and Heinz Langer. Notes on a Nevanlinna–Pick interpolation problem for generalized Nevanlinna functions. In Topics in interpolation theory (Leipzig, 1994), volume 95 of Oper. Theory Adv. Appl., pages 69–91. Birkhäuser, Basel, 1997.

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  77. H. Langer, A. Markus, and V. Matsaev. Locally definite operators in indefinite inner product spaces. Math. Ann., 308(3):405–424, 1997.

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  78. H. Langer, A.C.M. Ran, and D. Temme. Nonnegative solutions of algebraic Riccati equations. Linear Algebra Appl., 261:317–352, 1997.

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  79. H. Langer and B. Najman. Instability of singular critical points of definitizable operators. Integral Equations Operator Theory, 28(1):60–71, 1997.

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  80. H. Langer, V. Pivovarchik, and C. Tretter. Spectral properties of a compactly perturbed linear span of projections. Integral Equations Operator Theory, 26(3):353–366, 1996.

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  81. Heinz Langer, Reinhard Mennicken, and Christiane Tretter. A self-adjoint linear pencil Q − λP of ordinary differential operators. Methods Funct. Anal. Topology, 2(1):38–54, 1996.

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  82. M. Faierman and H. Langer. Elliptic problems involving an indefinite weight function. In Recent developments in operator theory and its applications (Winnipeg, MB, 1994), volume 87 of Oper. Theory Adv. Appl., pages 105–124. Birkhäuser, Basel, 1996.

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  83. Heinz Langer and Manfred Möller. The essential spectrum of a non-elliptic boundary value problem. Math. Nachr., 178:233–248, 1996.

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  84. Vadim Adamyan, Heinz Langer, Reinhard Mennicken, and Josef Saurer. Spectral components of selfadjoint block operator matrices with unbounded entries. Math. Nachr., 178:43–80, 1996.

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  85. Aad Dijksma and Heinz Langer. Operator theory and ordinary differential operators. In Lectures on operator theory and its applications (Waterloo, ON, 1994), volume 3 of Fields Inst. Monogr., pages 73–139. Amer. Math. Soc., Providence, RI, 1996.

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  86. Albrecht Böttcher, Aad Dijksma, Heinz Langer, Michael A. Dritschel, James Rovnyak, and M.A. Kaashoek. Lectures on operator theory and its applications, volume 3 of Fields Institute Monographs. American Mathematical Society, Providence, RI, 1996. Lectures presented at the meeting held at the Fields Institute for Research in Mathematical Sciences, Waterloo, Ontario, September 1994, Edited by Peter Lancaster.

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  87. Seppo Hassi, Heinz Langer, and Henk de Snoo. Selfadjoint extensions for a class of symmetric operators with defect numbers (1, 1). In Topics in operator theory, operator algebras and applications (Timişoara, 1994), pages 115–145. Rom. Acad., Bucharest, 1995.

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  88. Peter Jonas and Heinz Langer. Selfadjoint extensions of a closed linear relation of defect one in a Kreĭn space. In Operator theory and boundary eigenvalue problems (Vienna, 1993), volume 80 of Oper. Theory Adv. Appl., pages 176–205. Birkhäuser, Basel, 1995.

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  89. Vadim M. Adamjan and Heinz Langer. Spectral properties of a class of rational operator valued functions. J. Operator Theory, 33(2):259–277, 1995.

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  90. T.Ya. Azizov, Yu.P. Ginzburg, and G. Langer. On the work of M.G. Kreĭn in the theory of spaces with an indefinite metric. Ukraïn. Mat. Zh., 46(1-2):5–17, 1994.

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  91. F.V. Atkinson, H. Langer, R. Mennicken, and A.A. Shkalikov. The essential spectrum of some matrix operators. Math. Nachr., 167:5–20, 1994.

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  92. M. Faierman, H. Langer, R. Mennicken, and M. M¨oller. On an elliptic boundary value problem arising in magnetohydrodynamics. Quaestiones Math., 17(2):141–159, 1994.

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  93. Aad Dijksma, Heinz Langer, and Henk de Snoo. Eigenvalues and pole functions of Hamiltonian systems with eigenvalue depending boundary conditions. Math. Nachr., 161:107–154, 1993.

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  94. F.V. Atkinson, H. Langer, and R. Mennicken. Sturm–Liouville problems with coefficients which depend analytically on the eigenvalue parameter. Acta Sci. Math. (Szeged), 57(1-4):25–44, 1993.

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  95. Heinz Langer, Reinhard Mennicken, and Manfred Möller. Expansion of analytic functions in series of Floquet solutions of first order differential systems. Math. Nachr., 162:279–314, 1993.

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  96. T.Ja. Azizov and H. Langer. Some spectral properties of contractive and expansive operators in indefinite inner product spaces. Math. Nachr., 162:247–259, 1993.

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  97. Heinz Langer, Reinhard Mennicken,Manfred Möller, and Alfred Sattler. Expansions of analytic functions in products of Bessel functions. Results Math., 24(1-2):129–146, 1993.

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  98. H. Langer and B. Najman. Leading coefficients of the eigenvalues of perturbed analytic matrix functions. Integral Equations Operator Theory, 16(4):600–604, 1993.

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  99. P. Jonas, H. Langer, and B. Textorius. Models and unitary equivalence of cyclic selfadjoint operators in Pontrjagin spaces. In Operator theory and complex analysis (Sapporo, 1991), volume 59 of Oper. Theory Adv. Appl., pages 252–284. Birkhäuser, Basel, 1992.

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  100. H. Langer and B. Najman. Remarks on the perturbation of analytic matrix functions. III. Integral Equations Operator Theory, 15(5):796–806, 1992.

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  101. H. Langer, B. Najman, and K. Veselić. Perturbation of the eigenvalues of quadratic matrix polynomials. SIAM J. Matrix Anal. Appl., 13(2):474–489, 1992.

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  102. Heinz Langer, Reinhard Mennicken, and Manfred Möller. On Floquet eigenvalue problems for first order differential systems in the complex domain. J. Reine Angew. Math., 425:87–121, 1992.

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  103. H. Langer and A. Schneider. Some remarks about polynomials which are orthogonal with respect to an indefinite weight. Results Math., 21(1-2):152–164, 1992.

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  104. H. Langer and A. Schneider. On spectral properties of regular quasidefinite pencils F − λG. Results Math., 19(1-2):89–109, 1991.

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  105. Heinz Langer and Manfred Möller. Linearization of boundary eigenvalue problems. Integral Equations Operator Theory, 14(1):105–119, 1991.

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  106. H. Langer, R. Mennicken, and M. Möller. A second order differential operator depending non-linearly on the eigenvalue parameter. In Topics in operator theory: Ernst D. Hellinger memorial volume, volume 48 of Oper. Theory Adv. Appl., pages 319–332. Birkhäuser, Basel, 1990.

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  107. Aad Dijksma, Heinz Langer, and Henk de Snoo. Generalized coresolvents of standard isometric operators and generalized resolvents of standard symmetric relations in Kreĭn spaces. In Topics in operator theory: Ernst D. Hellinger memorial volume, volume 48 of Oper. Theory Adv. Appl., pages 261–274. Birkhäuser, Basel, 1990.

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  108. H. Langer and W. Schenk. Generalized second-order differential operators, corresponding gap diffusions and superharmonic transformations. Math. Nachr., 148:7–45, 1990.

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  109. Heinz Langer and Zoltán Sasvári. Definitizing polynomials of unitary and Hermitian operators in Pontrjagin spaces. Math. Ann., 288(2):231–243, 1990.

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  110. H. Langer and R. Mennicken. A transformation of right-definite S-Hermitian systems to canonical systems. Differential Integral Equations, 3(5):901–908, 1990.

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  111. H. Langer and W. Schenk. Time reversal of transient gap diffusions. In Markov processes and control theory (Gaußig, 1988), volume 54 of Math. Res., pages 104–114. Akademie-Verlag, Berlin, 1989.

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  112. B. Ćurgus, A. Dijksma, H. Langer, and H.S.V. de Snoo. Characteristic functions of unitary colligations and of bounded operators in Kreĭn spaces. In The Gohberg anniversary collection, Vol. II (Calgary, AB, 1988), volume 41 of Oper. Theory Adv. Appl., pages 125–152. Birkhäuser, Basel, 1989.

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  113. H. Langer and B. Najman. Remarks on the perturbation of analytic matrix functions. II. Integral Equations Operator Theory, 12(3):392–407, 1989.

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  114. Branko Ćurgus and Heinz Langer. A Kreĭn space approach to symmetric ordinary differential operators with an indefinite weight function. J. Differential Equations, 79(1):31–61, 1989.

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  115. Aad Dijksma, Heinz Langer, and Henk de Snoo. Hamiltonian systems with eigenvalue depending boundary conditions. In Contributions to operator theory and its applications (Mesa, AZ, 1987), volume 35 of Oper. Theory Adv. Appl., pages 37–83. Birkhäuser, Basel, 1988.

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  152. K. Harbarth and H. Langer. A factorization theorem for operator pencils. Integral Equations Operator Theory, 2(3):344–364, 1979.

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  155. H. Langer and B. Textorius. A generalization of M.G. Kreĭn’s method of directing functionals to linear relations. Proc. Roy. Soc. Edinburgh Sect. A, 81(3-4):237–246, 1978.

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  156. M.G. Kreĭn and H. Langer. On some mathematical principles in the linear theory of damped oscillations of continua. I. Integral Equations Operator Theory, 1(3):364–399, 1978. Translated from the Russian by R. Troelstra.

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  157. Heinz Langer. Sturm–Liouville problems with indefinite weight function and operators in spaces with indefinite metric. In Differential equations (Proc. Internat. Conf., Uppsala, 1977), pages 114–124. Sympos. Univ. Upsaliensis Ann. Quingentesimum Celebrantis, No. 7. Almqvist & Wiksell, Stockholm, 1977.

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  160. H. Langer and B. Textorius. On generalized resolvents and Q-functions of symmetric linear relations (subspaces) in Hilbert space. Pacific J. Math., 72(1):135–165, 1977.

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  162. Heinz Langer. Béla Szőkefalvi-Nagy is 65 years old. Mat. Lapok, 27(1-2):7–24 (1978), 1976.

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  163. M.G. Kreĭn and G.K. Langer. The indefinite power moment problem. Dokl. Akad. Nauk SSSR, 226(2):261–264, 1976.

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  165. Heinz Langer. Absolutstetigkeit der Übergangsfunktion einer Klasse eindimensionaler Fellerprozesse. Math. Nachr., 75:101–112, 1976.

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  168. Heinz Langer. Invariant subspaces for a class of operators in spaces with indefinite metric. J. Functional Analysis, 19:232–241, 1975.

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  169. Heinz Langer. Zur Spektraltheorie polynomialer Scharen selbstadjungierter Operatoren. Math. Nachr., 65:301–319, 1975.

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  170. Heinz Langer and Pekka Sorjonen. Verallgemeinerte Resolventen hermitescher und isometrischer Operatoren im Pontrjaginraum. Ann. Acad. Sci. Fenn. Ser. A I, (561):45, 1974.

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  171. M. Großmann and H. Langer. Über indexerhaltende Erweiterungen eines hermiteschen Operators im Pontrjaginraum. Math. Nachr., 64:289–317, 1974.

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  172. H. Langer, G. Maibaum, and P.H. Müller. Zu einem Satz über Verteilungen quadratischer Formen in Hilberträumen. Math. Nachr., 61:175–179, 1974.

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  178. M.G. Kreĭn and H. Langer. Über die verallgemeinerten Resolventen und die charakteristische Funktion eines isometrischen Operators im Raume Π κ . In Hilbert space operators and operator algebras (Proc. Internat. Conf., Tihany, 1970), pages 353–399. Colloq. Math. Soc. János Bolyai, 5. North-Holland, Amsterdam, 1972.

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  179. Heinz Langer. Verallgemeinerte Resolventen eines J-nichtnegativen Operators mit endlichem Defekt. J. Functional Analysis, 8:287–320, 1971.

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  180. H. Langer, L. Partzsch, and D. Schütze. Über verallgemeinerte gewöhnliche Differentialoperatoren mit nichtlokalen Randbedingungen und die von ihnen erzeugten Markov-Prozesse. Publ. Res. Inst. Math. Sci., 7:659–702, 1971/72.

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  181. G.K. Langer. The generalized coresolvents of a π-isometric operator with unequal defect numbers. Funkcional. Anal. i Priložen., 5(4):73–75, 1971.

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  182. Heinz Langer. Invariante Teilräume definisierbarer J-selbstadjungierter Operatoren. Ann. Acad. Sci. Fenn. Ser. A I No., 475:23, 1971.

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  183. M.G. Kreĭn and G.K. Langer. The defect subspaces and generalized resolvents of a Hermitian operator in the space Π κ . Funkcional. Anal. i Priložen, 5(3):54–69, 1971.

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  184. M.G. Kreĭn and G.K. Langer. The defect subspaces and generalized resolvents of a Hermitian operator in the space Π κ . Funkcional. Anal. i Priložen, 5(2):59–71, 1971.

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  185. H. Langer. Über die Methode der richtenden Funktionale von M.G. Krein. Acta Math. Acad. Sci. Hungar., 21:207–224, 1970.

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  186. G. Langer. Maximal dual pairs of invariant subspaces of J-self-adjoint operators. Mat. Zametki, 7:443–447, 1970.

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  187. G.K. Langer. A remark on invariant subspaces of linear operators in Banach spaces with indefinite metric. Mat. Issled., 4(vyp. 1 (11)):27–34, 1969.

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  188. Heinz Langer. Über die schwache Stabilität linearer Differentialgleichungen mit periodischen Koeffizienten. Math. Scand., 22:203–208, 1968.

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  189. Heinz Langer. Über Lancaster’s Zerlegung von Matrizen-Scharen. Arch. Rational Mech. Anal., 29:75–80, 1968.

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  190. Heinz Langer. Über einen Satz von M.A. Neumark. Math. Ann., 175:303–314, 1968.

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  191. Heinz Langer. Über stark gedämpfte Scharen im Hilbertraum. J. Math. Mech., 17:685–705, 1967/1968.

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  192. Heinz Langer. Spektralfunktionen einer Klasse J-selbstadjungierter Operatoren. Math. Nachr., 33:107–120, 1967.

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  193. Heinz Langer and Volker Nollau. Einige Bemerkungen über dissipative Operatoren im Hilbertraum. Wiss. Z. Techn. Univ. Dresden, 15:669–673, 1966.

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  194. G.K. Langer. Invariant subspaces of linear operators acting in a space with indefinite metric. Dokl. Akad. Nauk SSSR, 169:12–15, 1966.

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  195. Heinz Langer. Eine Erweiterung der Spurformel der Störungstheorie. Math. Nachr., 30:123–135, 1965.

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  198. M.G. Kreĭn and G.K. Langer. On the spectral function of a self-adjoint operator in a space with indefinite metric. Dokl. Akad. Nauk SSSR, 152:39–42, 1963.

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  199. Heinz Langer. Eine Verallgemeinerung eines Satzes von L.S. Pontrjagin. Math. Ann., 152:434–436, 1963.

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  200. H. Langer. Über die Wurzeln eines maximalen dissipativen Operators. Acta Math. Acad. Sci. Hungar., 13:415–424, 1962.

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  201. Heinz Langer. Zur Spektraltheorie J-selbstadjungierter Operatoren. Math. Ann., 146:60–85, 1962.

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  1. Department of Mathematics, Chapman University, Orange, CA, USA

    Daniel Alpay

  2. Mathematisches Institut, Universität Leipzig, Leipzig, Germany

    Bernd Kirstein

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Alpay, D., Kirstein, B. (2018). List of Publications* of Professor Dr. Dr. h.c. mult. Heinz Langer. In: Alpay, D., Kirstein, B. (eds) Indefinite Inner Product Spaces, Schur Analysis, and Differential Equations. Operator Theory: Advances and Applications(), vol 263. Birkhäuser, Cham. https://doi.org/10.1007/978-3-319-68849-7_1

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