Seminar notes

• A posteriori Eigenvalue error estimations for nonselfadjoint operator approximation February-April 2012
• About Regularization in Hilbert Space

Publications

• Regularization methods for unbounded linear operators. J. Inverse Ill-Posed Probl. 18 (2010), no. 6, 647–653.
• Spectra of approximating operators. Mat. Stos. 38 (1995), 87–100.
• On an infinite-dimensional version of the Kreiss matrix theorem. Numerical analysis and mathematical modelling, 45–50, Banach Center Publ., 29, Polish Acad. Sci., Warsaw, 1994.
• Perturbation of the spectrum of an essentially selfadjoint operator. Appl. Math. (Warsaw) 22 (1993), no. 1, 75–89.
• with van Ban, D.; Moszynski, K. A.Semi-iterative methods for linear equations. Mat. Stos. 35 (1992), 5–19.
• with T. Reginska,A class of regularization methods for ill posed problems. Numer. Funct. Anal. Optim. 11 (1990), no. 1-2, 119–138.
• Unitarily invariant class of matrices with powers without vanishing diagonal entries . Linear and Multilinear Algebra 21 (1987), no. 4, 373–384.
• On perturbations and the equivalence orbit of a matrix pencil. Linear Algebra Appl. 82 (1986), 99–121.
• Determination of eigenvalues and eigenvectors by means of iterations of subspaces. (Polish) Mat. Stos. 24 (1985), 105–122.
• On the distance between spectra. (Polish) Mat. Stos. 24 (1985), 93–103.
• Matrices that split the norm and their application in the theory of stability of difference schemes. (Polish) Mat. Stos. 26 (1985), 29–47, 229–230.
• On continuity of spectra in norm ideals. Linear Algebra Appl. 69 (1985), 121–130.
• Limits of spectra of strongly converging compressions. J. Operator Theory 12 (1984), no. 2, 199–212.
• A characterization of the Weyl spectrum. Proc. Amer. Math. Soc. 92 (1984), no. 2, 215–218.
• Spectral approximation of positive operators by iteration subspace method. Apl. Mat. 29 (1984), no. 2, 104–113.
• Method of orthogonal projections and approximation of the spectrum of a bounded operator. II. Studia Math. 70 (1981), no. 1, 1–9.
• Spectra of operators with fixed imaginary parts. Proc. Amer. Math. Soc. 81 (1981), no. 3, 359–364.
• Spectra of compressions of an operator with compact imaginary part. J. Operator Theory 3 (1980), no. 2, 151–158.
• Method of orthogonal projections and approximation of the spectrum of a bounded operator. Studia Math. 65 (1979), no. 1, 21–29.
• with K. Moszynski, Some remarks on spectral approximation for compact operators. (Polish) Mat. Stos. (3) 12 (1978), 5–16.
• with K. Moszynski,Sur les systčmes infinis d'équations différentielles ordinaires dans certains espaces de Fréchet. (French) Dissertationes Math. (Rozprawy Mat.) 115 (1974), 37 pp.