List of Publications

• I. Lewkowicz, ``On Hyper-Lyapunov Matrix Inclusions", to appear in Linear Algebra and its Applications.
  

• D. Alpay and I. Lewkowicz, ``Quatitatively Hyper-Positive Real Rational Functions II", to appear in Linear Algebra and its Applications.
  

• D. Alpay, I. Lewkowicz and M. Vajiac, ``Interpolation with Symmetry and Herglotz Theorem in the Bicomplex Setting", to appear in Journal of Mathematical Analysis and Applications, Vol. 524, paper no. 127201, 2023.
  

• D. Alpay and I. Lewkowicz, ``On Realizations of Left and Right Products of Rational Functions", Linear Algebra and its Applications, Vol. 666, pp. 42-61, 2023.
  

• D. Alpay, I. Lewkowicz and M. Vajiac, ``Discrete Wiener Algebra in the Bicomplex Setting, Spectral Factorization with Symmetry, and Superoscilations", Annalysis and Mathematical Physics, Vol. 13, article 54, 2023.
  

• D. Alpay, P.E.T. Jorgensen and I. Lewkowicz, ``Representation Theory and Multilevel Filters", Journal of Applied Mathematics and Computing, Vol. 69, pp. 1599-1657, 2023.
  

• I. Lewkowicz, ``Passive Linear Discrete-Time Systems: Characterization Through Structure", Linear Algebra and its Applications, no. 15718, 2021.
  

• D. Alpay and I. Lewkowicz, ``Quantitatively Hyper-Positive Real Functions", Linear Algebra and its Applications, no. 15643, 2021.
  

• I. Lewkowicz, ``Passive Linear Continuous-Time Systems: Characterization Through Structure", Systems and Control Letters, Vol. 147, no. 104819, 2021.
  

• D. Alpay, F. Colombo, I. Lewkowicz and I. Sabadini, ``On Pseudo-Spectral Factorization over the Complex Number and Quaternions", Linear Algebra and its Applications, Vol. 606. pp. 90-126, 2020.
  

• D. Alpay and I. Lewkowicz, ``Composition of Rational Functions: State-Space Realization and Applications", Linear Algebra and its Applications, Vol. 580. pp. 359-383, 2019.
  

• D. Alpay, F. Colombo, I. Lewkowicz and I. Sabadini, ``Positive and Generalized Positive Real Lemma for Slice Hyperholomorphic Functions", Integral Equations and Operator Theory, Vol. 91, article No. 4, 2019
  

• D. Alpay and I. Lewkowicz, ``Realization of Tensor-Product and of Tensor-Fractorization of Rational Functions," Quantum Studies: Mathematics and Foundations Vol. 6, pp. 269-278, 2019
  

• K. Abu-Ghanem, D. Alpay, F. Colombo, I. Lewkowicz and I. Sabadini, ``Herglotz Functions of Several Quaternionic Variables", J. Math. Anal. and Appl. Vol. 466, pp. 169-189, 2018
  

• D. Alpay and I. Lewkowicz, "Wrong Side Interpolation by Positive Real Rational Functions", Linear Algebra and its Applications Vol. 539, pp. 175-197, 2018.
  

• D. Alpay, P.E.T. Jorgensen and I. Lewkowicz, ``W-Markov Measures Transfer Operators, Wavelets and Multiresolution", AMS Contamporary Mathematics Vol. 706, pp. 293-343, 2018.
  

• D. Alpay, P.E.T. Jorgensen and I. Lewkowicz, ``Characterizations of Families of Rectangular, Finite Impulse Response, Para-Unitary Systems", Journal of Applied Mathematics & Computing Vol. 54, pp. 395-423, 2017.
  

• D. Alpay, P.E.T. Jorgensen and I. Lewkowicz, ``Characterizations of Rectangular (Para)-Unitary Rational Functions", Opuscula Mathematica Vol. 36, pp. 695-716, 2016.
  

• D. Alpay, P.E.T. Jorgensen, I. Lewkowicz and D. Volok, ``A New Realization of Rational Functions with Applications to Linear Combination Interpolation", Int. J. of Complex Variables and Elliptic Equations Vol. 61, pp. 42-54, 2016.
  

• D. Alpay, P.E.T. Jorgensen and I. Lewkowicz, ``Realizations of Infinite Products, Ruelle Operators and Wavelet Filters", The J. of Fourier Analysis and Applications Vol. 21, pp. 1034-1052, 2015.
  

• D. Alpay, F. Colombo, I. Lewkowicz and I.M. Sabadini "Realizations of Slice Hyperholomorphic Generalized Contractive and Positive Functions", Milan Journal of Mathematics Springer-Birkhauser, Vol. 83, pp. 91-144, 2015.
  

• D. Alpay, P.E.T. Jorgensen, I. Lewkowicz and I. Marziano, "Infinite product representations for kernels and iteration of functions", Operator Theory: Advances and Applications Vol. 244, pp. 67-87, Springer-Birkhauser, 2015.
  

• D. Alpay and I. Lewkowicz, "Interpolation by Polynomials with Symmetries", Linear Algebra and its Applications, Vol. 456, pp. 64-81, 2014.
  

• D. Alpay, P. Jorgensen and I. Lewkowicz, "Parameterizations of all wavelet filters: input-output and state-space", Sampling Theory in Signal and Image Processing. Vol. 12, pp. 159-188, 2013.
  

• D. Alpay, P. Jorgensen, I. Lewkowicz and I. Marziano. "Representation Formulas for Hardy space functions through the Cuntz relations and new interpolation problems", Multiscale Signal Analysis and Modeling, (editors Xiaoping Shen and Ahmed Zayed), in the series Lecture Notes in Electrical Engineering, pp. 161-182, Springer, 2013.
  

• D. Alpay and I. Lewkowicz, "Convex Cones of Generalized Positive Rational Functions and Nevanlinna-Pick Interpolation", Linear Algebra and its Applications, Vol. 438, pp. 3949-3966, 2013.
  

• D. Alpay, P.E.T Jorgensen, and I. Lewkowicz Extending Wavelet Filters. Infinite-dimensions, the Non-rational case and Indefinite-inner Product Spaces", Excursions in Harmonic Analysis Book Series, Volume 2, Chapter 5, pp. 69-112, Springer-Birkhauser, 2013
  

• D. Alpay and I. Lewkowicz, "The Positive Real Lemma and Construction of all Realizations of Generalized Positive Rational Functions", Systems and Control Letters, Vol. 60, pp. 985-993, 2011
  

• D. Alpay and I. Lewkowicz, "An Easy to Compute Factorization of Rational Generalized Positive Functions", Systems and Control Letters, Vol. 59, pp. 517-521, 2010
  

• N. Cohen and I. Lewkowicz, "The Lyapunov Order for Real Matrices", Linear Algebra and its Applications, Vol. 430, pp. 1849-1866, 2009
  

• N. Cohen and I. Lewkowicz, "Convex Invertible Cones and Positive Real Analytic Functions", Linear Algebra and its Applications, Vol. 425, pp. 797-813, 2007
  

• I. Lewkowicz, L. Rodman and E. J. Yarkoni, "Convex Invertible Sets and Matrix Sign Function", Linear Algebra and its Applications, Vol. 396, pp. 329-352, 2005
  

• N. Cohen and I. Lewkowicz, "A Pair of Matrices Sharing Common Lyapunov Solutions - A Closer Look", Linear Algebra and its Applications, Vol. 370, pp. 83-104, 2003
  

• N. Cohen and I. Lewkowicz, "A Characterization of Convex Cones of Matrices with Constant Regular Inertia", Linear Algebra and its Applications, Vol. 318, pp. 23-33, 2000
  

• I. Lewkowicz, "A Necessary Condition for Quantitative Exponential Stability of Linear State Space Systems", Systems and Control Letters, Vol. 38, pp. 1-4, September 1999.
  

• I. Lewkowicz, "Convex Invertible Cones of Matrices - a Unified Framework for the Equations of Sylvester, Lyapunov and Riccati", Linear Algebra and its Applications, Vol. 286, pp 107-133, 1999.
  

• N. Cohen and I. Lewkowicz, "Convex Invertible Cones of State Space Systems", Mathematics of Control Signals and Systems, Vol. 10, pp. 265-285, 1997.
  

• N. Cohen, I. Lewkowicz and L. Rodman, "Exponential Stability of Triangular Differential Inclusion Systems", Systems and Control Letters, Vol. 30, pp. 159-164, May 1997.
  

• N. Cohen and I. Lewkowicz, "Convex Invertible Cones and the Lyapunov Equation", Linear Algebra and its Applications, Vol. 250, pp. 105-131, January 1997.
  

• N. Cohen and I. Lewkowicz, "A Necessary and Sufficient Criterion for the Stability of a Convex Set of Matrices", IEEE Trans. Auto. Contr., Vol. AC-38, No. 4, pp. 611-615, 1993.
  

• I. Lewkowicz and R. Sivan, "Stability Robustness of Almost Linear State Equations", IEEE Trans. Auto. Contr., Vol. AC-38, No. 2, pp. 262-266, 1993.
  

• I. Lewkowicz, "When Are the Complex and the Real Stability Radii Equal?", IEEE Trans. Auto. Contr., Vol. AC-37, No. 6, pp. 880-883, June 1992.
  

• N. Cohen and I. Lewkowicz, "Bounds for the Singular Values Based on the Eigenvectors, Linear Algebra and its Applications, Vol. 149, pp. 227-248, April 1991.
  

• I. Lewkowicz and R. Sivan, "Inverse Radial Matrices and Maximal Stability Robustness", in Control of Uncertain Systems: Proc. of an International Workshop, Bremen, West-Germany, June 1989, Birkhauser, 1990.
  

• I. Lewkowicz, "Remarks on Inequality in Johnson's Lower Bound for the Smallest Singular Value", Linear Algebra and its Applications, Vol. 120, pp. 39-46, 1989.
  

• I. Lewkowicz, "Bounds for the Singular Values of a Matrix with Non - Negative Eigenvalues", Linear Algebra and its Applications, Vol. 112, pp. 29-37, Jan. 1989.
  

• I. Lewkowicz and R. Sivan, "Maximal Stability Robustness for State Equations", IEEE Trans. Auto. Contr., Vol. AC-33, No. 3, pp. 297-300, March 1988.

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