Department of Complex Analysis and Potential Theory

Vitalii Shpakivskyi

Doctor of Sciences

Senior Researcher, Institute of Mathematics
of the National Academy of Sciences of Ukraine

ORCID: 0000-0003-4256-8975

e-mail: shpakivskyi86@gmail.com

  • 2019 - present - Senior Research Fellow, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2020 - 2024 - Secretary of the Hlybochytsia Village Council, Zhytomyr district, Zhytomyr region, Ukraine, Padova, Italy
  • 2018 - 2020 - Doctoral student, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2014 - 2019 - Research Fellow, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2011 - 2014 - Junior Research Fellow, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2008 - 2011 - PhD student, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2008 - 2013 - Assistant of the Department of Mathematical Analysis, Zhytomyr Ivan Franko State University, Zhytomyr, Ukraine
  • 2020 - Doctor of Sciences (in Physics and Mathematics, Mathematical Analysis). Dissertation Title: Monogenic functions in commutative algebras, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2018 - 2020 - Doctoral studies, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2011 - Ph.D. (in Physics and Mathematics, Mathematical Analysis). Theses: Integral theorems for monogenic functions in three-dimensional harmonic algebra, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2008 - 2011 - Ph.D. studies under the guidance of Professor S. A. Plaksa, Institute of Mathematics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
  • 2003 - 2008 - Master's degree, diploma with honors, Faculty of Physics and Mathematics, Zhytomyr Ivan Franko State University, Zhytomyr, Ukraine
  • 2000 - 2003 - Physics and mathematics class, Zhytomyr Regional Pedagogical Lyceum, Zhytomyr, Ukraine
  • 1992 - 2000 - Hadzynka Secondary School of I-II Degrees, Zhytomyr Region, Ukraine
  • Complex and Hypercomplex Analysis
  • Monogenic Function Theory in Banach Algebras
  • Analytic Function Theory of Complex Variable
  • Algebra and Analysis in Non-commutative algebras
  • 1. We have developed an algebraic-analytic approach to equations in mathematical physics. The idea of ​​this approach is to find commutative Banach algebras such that the monogenic functions given in them form an algebra and have components that satisfy the given partial differential equations. We have obtained a constructive description of monogenic functions defined in the domains of special subspaces of an arbitrary finite-dimensional commutative associative algebra over the field C, with values ​​in this algebra using holomorphic functions of a complex variable.
  • 2. Analogues of integral theorems (Cauchy integral theorem for curvilinear and surface integrals, Cauchy integral formula, Morera theorem) are proved for monogenic functions with values ​​in an arbitrary finite-dimensional commutative associative algebra, as well as in an infinite-dimensional commutative algebra and a topological vector space with commutative multiplication, associated with the three-dimensional Laplace equation.
  • 3. The relations between monogenic functions with values ​​in algebras that form a sequence of extensions of commutative algebras of a certain class is established. The indicated monogenic functions are used to construct an infinite-dimensional family of solutions of linear homogeneous PDEs with constant coefficients.
  • 4. Various types of differentiability in the algebra of complex quaternions are studied. A class of quaternion G-monogenic mappings is introduced and their constructive description is obtained using holomorphic functions of a complex variable; analogues of integral theorems for mappings of this class are proved. A relation is established between the known classes of quaternion differential functions and functions analytic according to Hausdorff, and a connection is established between the known definitions of derivatives and the Hausdorff derivative.
  • 5. An algorithm for constructing functions belonging to the kernel of the Dirac operator in generalized Cayley-Dickson algebras has been developed. A constructive description of various classes of hyperholomorphic functions in the algebra of complex quaternions has been obtained.
  • Books:
  • 2023 - Plaksa S.A. and Shpakivskyi V.S. Monogenic functions in spaces with commutative multiplication and applications. Frontiers in Mathematics, Birkhäuser Cham.
    DOI: 10.1007/978-3-031-32254-9
  • Chapters in books or edited volumes:
  • 2009 - Shpakivskyi V. S., Plaksa S. A. Integral theorems in a commutative three-dimensional harmonic. In: Progress in Analysis and its Applications: Proc. of the 7th Intern. ISAAC Congress, London: World Scientific, 2009, 232 – 239. DOI: 10.1142/7791
  • 2010 - Shpakivskyi V. S. Power series and Laurent series in three-dimensional harmonic algebra. In: Proc. of the Institute of Mathematics of the National Academy of Sciences of Ukraine, 9,No. 2, 384 – 391.
  • 2012 - Shpakivskyi V. S. On the isomorphism of functional algebras in a harmonic algebra with a two-dimensional radical. In: Proc. of the Institute of Mathematics of the National Academy of Sciences of Ukraine, 7,No. 2, 314 – 321.
  • 2013 - Shpakivskyi V. S., Kuzmenko T. S. Monogenic functions of double variable, In: Proc. of the Institute of Mathematics of the National Academy of Sciences of Ukraine, 10,No. 4-5, 372 – 378.
  • 2015 - Shpakivskyi V. S. Monogenic functions in finite-dimensional commutative associative algebras , In: Proc. of the Institute of Mathematics of the National Academy of Sciences of Ukraine, 12,No. 3, 251 – 268.
  • 2015 - Shpakivskyi V. S. Integral theorems for monogenic functions in commutative algebras , In: Proc. of the Institute of Mathematics of the National Academy of Sciences of Ukraine, 12,No. 4, 313 – 328.
  • 2019 - Kuzmenko T. S., Shpakivskyi V. S. A theory of quaternionic G-monogenic mappings in E_3 , In: Models and Theories in Social Systems (Eds. C. Flaut etc.). – Springer, Vol. 179. – P. 451 – 508.
    DOI: 10.1007/978-3-030-00084-4
  • 2019 - Shpakivskyi V. Monogenic functions in commutative algebras , In:Analysis, Probability, Applications, and Computation, Trends in Mathematics, (Eds. K.-O. Lindahl et al.). – Springer, 2019. – P. 171 – 178.
    DOI: 10.1007/978-3-030-04459-6
  • 2022 - Shpakivskyi V. S. Sigma-monogenic functions in commutative algebras (Ukrainian), In: Proc. of the Institute of Mathematics of the National Academy of Sciences of Ukraine, 19,No. 1, 231 – 256.
  • 2023 - Plaksa S. A., Shpakivskyi V. S. Integral theorems in finite-dimensional commutative algebra (Ukrainian), In: Proc. of the Institute of Mathematics of the National Academy of Sciences of Ukraine, 20,No. 1, 911 – 946.
  • Selected publications in scientific journals:
  • 2008 - Mierzejewski D. A., Szpakowski V. S. On solutions of some types of quaternionic quadratic equations, Bulletin de la Société des Sciences et des Lettres de Łódź 58, Ser. Recherches sur les déformations, Vol.55, 49 – 58.
  • 2009 - Szpakowski V. S. Solution of general quadratic quaternionic equations , Bulletin de la Société des Sciences et des Lettres de Łódź 59, Ser. Recherches sur les déformations, Vol. 58, 45 – 58.
  • 2010 - Plaksa S.A. and Shpakivskyi V.S. Integral theorems for differentiable functions in three-dimensional harmonic algebra, Reports of the National Academy of Sciences of Ukraine, 5, 23 - 30.
  • 2010 - Shpakivskyi V.S. and Plaksa S.A. Integral theorems and a Cauchy formula in a commutative three-dimensional harmonic algebra, Bulletin de la Societe des Sciences et des Lettres de Lodz, 60(2), 47-54
  • 2011 - Plaksa S.A. and Shpakivskyi V.S. Constructive description of monogenic functions in a harmonic algebra of the third rank, Ukr. Math. J., 62(8), 1078-1091.
    DOI: 10.1007/s11253-011-0427-x
  • 2011 - Shpakivskyi V. S. Linear quaternionic equations and their systems, Advances in Applied Clifford Algebras, Vol. 21, No. 3, 637 – 645.
    DOI: 10.1007/s00006-010-0264-2
  • 2011 - Plaksa S.A., Gryshchuk S.V. and Shpakivskyi V.S. Commutative algebras of monogenic functions associated with classic equations of mathematical physics, Contemporary Mathematics, 553, Amer. Math. Soc., Providence, 245-258.
    DOI: 10.1090/conm/553
  • 2012 - Plaksa S.A. and Shpakivskyi V.S. Limiting values of Cauchy type integral in a three-dimensional harmonic algebra, Eurasian Math. J., 3(2), 120-128
  • 2012 - Plaksa S.A. and Shpakivskyi V.S. A description of spatial potential fields by means of monogenic functions in infinite-dimensional spaces with a commutative multiplication, Bulletin de la Societe des Sciences et des Lettres de Lodz, 62(2), 55-65
  • 2013 - Plaksa S.A. and Shpakivskyi V.S. On the logarithmic residues of monogenic functions in a three-dimensional harmonic algebra with two-dimensional radical, Ukr. Math. J., 65(7), 1079-1086.
    DOI: 10.1007/s11253-013-0843-1
  • 2013 - Plaksa S.A. and Shpakivskyi V.S. On limiting values of Cauchy type integral in a harmonic algebra with two-dimensional radical, Annales Universitatis Mariae Curie-Sklodowska. Sectio A, 67(1), 57-64
  • 2013 - Flaut C., Shpakivskyi V. Some identities in algebras obtained by the Cayle-Dickson process, Advances in Applied Clifford Algebras, Vol. 23, No. 1, 63 – 76.
    DOI: 10.1007/s00006-012-0344-6
  • 2013 - Flaut C., Shpakivskyi V. Real matrix representations for the complex quaternions , Advances in Applied Clifford Algebras, Vol. 23, No. 3, 657 – 671.
    DOI: 10.1007/s00006-013-0387-3
  • 2013 - Flaut C., Shpakivskyi V. On Generalized Fibonacci Quaternions and Fibonacci-Narayana Quaternions , Advances in Applied Clifford Algebras, Vol. 23, No. 3, 673 – 688.
    DOI: 10.1007/s00006-013-0388-2
  • 2014 - Plaksa S.A. and Shpakivskyi V.S. Cauchy theorem for a surface integral in commutative algebras, Complex Variables and Elliptic Equations, 59(1), 110-119.
    DOI: 10.1080/17476933.2013.845178
  • 2014 - Plaksa S.A. and Shpakivskyi V.S. Monogenic functions in a finite-dimensional algebra with unit and radical of maximal dimensionality, Journal of Algerian Mathematical Society, 1, 1-13.
  • 2015 - Flaut C., Shpakivskyi V. Holomorphic functions in generalized Cayley-Dickson algebras, Advances in Applied Clifford Algebras, Vol. 25, No. 1, 95 – 112.
    DOI: 10.1007/s00006-014-0479-8
  • 2015 - Flaut C., Shpakivskyi V. An efficient method for solving equations in generalized quaternion and octonion algebras, Advances in Applied Clifford Algebras, Vol. 25, No. 2, 337 – 350.
    DOI: 10.1007/s00006-014-0493-x
  • 2015 - Shpakivskyi V. Constructive description of monogenic functions in finite-dimensional commutative algebras (Ukrainian), Reports of the National Academy of Sciences of Ukraine, 4, 23 - 28.
  • 2015 - Flaut C., Shpakivskyi V. Some remarks about Fibonacci elements in an arbitrary algebra, Bulletin de la Société des Sciences et des Lettres de Łódź, Ser. Recherches sur les déformations, 65, No. 3, 63 – 73.
    DOI: http://www.ltn.lodz.pl/streszczenia/Bulletin-65-3.pdf
  • 2016 - Shpakivskyi V. S., Kuzmenko T. S. On one class of quaternion mappings, Ukr. Math. J. 68, 127 - 143.
    DOI: 10.1007/s11253-016-1213-6
  • 2016 - Shpakivskyi V. S. Constructive description of monogenic functions in a finite-dimensional commutative associative algebra, Adv. Pure Appl. Math., Vol. 7, No. 1, 63 – 75.
    DOI: 10.1515/apam-2015-0022
  • 2016 - Shpakivskyi V. S., Kuzmenko T. S. Integral theorems for the quaternionic G-monogenic mappings, An. Şt. Univ. Ovidius Constanţa, 24, No. 2, 271 – 281.
    DOI: 10.1515/auom-2016-0042
  • 2016 - Shpakivskyi V. S. Curvilinear integral theorems for monogenic functions in commutative associative algebras, Advances in Applied Clifford Algebras, Vol. 26, No. 1, P. 417 – 434.
    DOI: 10.1007/s00006-015-0561-x"
  • 2016 - Shpakivskyi V. S., Kuzmenko T. S. On monogenic mappings of a quaternion variable, J. Math. Sci., 221, 712 – 726.
    DOI: 10.1007/s10958-017-3260-4
  • 2016 - Kuzmenko T. S., Shpakivskyi V. S. Generalized integral theorems for the quaternionic G-monogenic mappings, J. Math. Sci., 224, 530 – 540.
    DOI: 10.1007/s10958-017-3433-1
  • 2016 - Shpakivskyi V. S. Hypercomplex representation of analytical solutions of one hydrodynamic equation (Russian), Proceedings of the IPMM NAS of Ukraine, 30, 155 – 164.
    DOI: http://dspace.nbuv.gov.ua/handle/123456789/140867
  • 2017 - Plaksa S.A. and Shpakivskyi V.S. An extension of monogenic functions and spatial potentials, Lobachevskii Journal of Mathematics, 38(2), 330-337.
    DOI: 10.1134/S1995080217020160
  • 2017 - Flaut C., Shpakivskyi V., Vlad E. Some remarks regarding h(x)–Fibonacci polynomials in an arbitrary algebra, Chaos, Solitons and Fractals, Vol. 99, 32 – 35.
    DOI: 10.1016/j.chaos.2017.03.040
  • 2018 - Shpakivskyi V. S., Kuzmenko T. S. Quaternionic G-monogenic mappings in E_m, Int. J. Adv. Res. Math., Vol. 12, 1 – 34.
  • 2018 - Plaksa S.A. and Shpakivskyi V.S. Integral theorems for monogenic functions in an infinite-dimensional space with a commutative multiplication, Bulletin de la Societe des Sciences et des Lettres de Lodz, 68(2), 25-36
  • 2018 - Shpakivskyi V. S. On monogenic functions defined in different commutative algebras, J. Math. Sci. 239, 92 – 109.
    DOI: 10.1007/s10958-019-04291-0
  • 2018 - Shpakivskyi V. S. On monogene functions on extensions of commutative algebra (Ukrainian), Proceedings of the International Geometry Center, 11 (3), 1 - 18.
    DOI: 10.15673/tmgc.v11i3.1200
  • 2018 - Shpakivskyi V. S. Hypercomplex method for solving linear PDEs (Ukrainian), Proceedings of the IPMM NAS of Ukraine, 32, 147 – 168.
    DOI: https://drive.google.com/file/d/1vJDjKDJZVXx8gFstuPjxkZnfNIGUoN-d/view
  • 2019 - Luna-Elizarrarás M. E., Shapiro M., Shpakivskyi V. On the Hausdorff Analyticity for Quaternion-Valued Functions , Complex Analysis and Operator Theory, Vol. 13, No. 6, 2863 – 2880.
    DOI: 10.1007/s11785-018-0856-8
  • 2022 - Kuzmenko T. S., Shpakivskyi V. S. G-monogenic mappings in a three-dimensional noncommutative algebra, Complex Variables and Elliptic Equations, Vol. 67, No. 11, 2759 – 2769.
    DOI: 10.1080/17476933.2021.1947257
  • 2022 - Kuzmenko T. S., Shpakivskyi V. S. Differentiable functions in a three-dimensional associative noncommutative algebra , Advances in the Theory of Nonlinear Analysis and its Applications. Vol. 6, No. 1, 66 – 73.
    DOI: https://atnaea.org/index.php/journal/article/view/101
  • 2022 - Shpakivskyi V. S., Kuzmenko T. S. Hausdorff analytic functions in the three-dimensional associative noncommutative algebra, J. Math. Sci. 262, 207 – 221.
    DOI: 10.1007/s10958-022-05811-1
  • 2023 - Shpakivskyi V. S. Sigma-monogenic functions in commutative algebras, Proceedings of the International Geometry Center, Vol. 16, No. 1, 17 – 41.
    DOI: 10.15673/tmgc.v16i1.2421
  • 2023 - Shpakivskyi V. S. Conformable fractional derivative in commutative algebras, Journal of Mathematical Sciences, Vol. 274, No. 3, 392 – 402.
    DOI: 10.1007/s10958-023-06608-6
  • 2024 - Kuzmenko T. S., Shpakivskyi V. S. Representations of Some Classes of Quaternionic Hyperholomorphic Functions, Complex Analysis and Operator Theory, 18(5):116.
    DOI: 10.1007/s11785-024-01561-x
  • 2024 - Shpakivskyi V. S. Construction of solutions of PDEs using holomorphic functions of several variables, Electronic Journal of Differential Equations,Vol. 2024, No. 71, 1 - 12.
    DOI: 10.58997/ejde.2024.71
  • 2024 - Shpakivskyi V. S. Construction of an infinite-dimensional family of exact solutions of a three-dimensional biharmonic equation by the hypercomplex method, Advances in Applied Clifford Algebras, 35:5, 12 pp.
    DOI: 10.1007/s00006-024-01365-4
  • 2006 - The XI Kravchuk International Scientific Conference, (Ukraine, Kyiv);
  • 2007 - Conference “Modern problems of mathematics and its application in natural sciences and information technologies”, (Ukraine, Kharkiv);
  • 2007 - Bogolyubov Readings 2007. International Conference of Complex Analysis and Wave Processes in Mechanics, (Ukraine, Zhytomyr);
  • 2008 - The student scientific conference of the applied mathematics and informatics, (Ukraine, Lviv);
  • 2009 - International Scientific Conference dedicate to Prof. M.I. Nagnibida, (Ukraine, Chernivtsi);
  • 2009 - International Scientific Conference „Analytic methods of mechanics and complex analysis” dedicated to N. A. Kilchevskii and V.A.Zmorovich on the occasion of their birthday centenary”, (Ukraine, Kyiv) ;
  • 2009 - Hypercomplex Seminar 2009: From Schauder Basis to Hypercomplex, Randers-Ingarden and Fractal Structures, and Nanostructures, (Poland, Będlewo);
  • 2009 - 7th ISAAC Congress , (UK, London);
  • 2010 - Hypercomplex Seminar 2010: (Hyper)Complex and Randers-Ingarden Structures in Mathematics and Physics, (Poland, Będlewo) ;
  • 2010 - 6-th International Conference ”Finsler Extensions of Relativity Theory”, (Moscow, Russia);
  • 2011 - Conference on Analytic Functions and Related Topics, (Chelm, Poland);
  • 2013 - International workshop “A new approach in theoretical and applied methods in algebra and analysis”, (Constanta, Romania);
  • 2013 - International Conference "Complex Analysis, Potential Theory and Applications", (Kyiv, Ukraine);
  • 2013 - Joint events of Colloquium on Differential Geometry and its Applications and IX-th International Conference on Finsler Extensions of Relativity Theory, (Debrecen, Hungary);
  • 2014 - International Conference “Differential equations, computational mathematics, theory of functions and mathematical methods of mechanics” dedicate to 100th anniversary of Prof. G. M. Polozhii, (Kyiv, Ukraine);
  • 2015 - 10th ISAAC Congress, (Macau, China);
  • 2015 - X Summer School "Algebra, Topology, Analysis", (Odessa, Ukraine);
  • 2017 - 11th ISAAC Congress, (Växjö, Sweden);
  • 2018 - Hypercomplex Seminar 2018: (Hyper)Complex Analysis in Differential Equations, Geometry and Physical Applications, (Będlewo, Poland);
  • 2019 - 12th ISAAC Congress, (Aveiro, Portugal);
  • 2021 - (Hyper)Complex Seminar, (Bedlewo, Poland);
  • 2023 - International Conference of Young Mathematicians, (Kyiv, Ukraine);
  • 2024 - (Hyper)Complex Seminar, (Bedlewo, Poland);
  • 2024 - International conference dedicated to the 145th anniversary of the birth of Hans Hahn, Yu. Fedkovych Chernivtsi National University, (Chernivtsi, Ukraine);
  • Training courses for undergraduate and graduate students:
  • - Сomplex analysis
  • - Mathematical analysis
  • - Differential equations
  • - Theory of functions of a real variable
  • - Higher Mathematics (for managers)
  • Membership in Scientific Societies:
  • - Member of the IGO "Polish Scientific Society in Zhytomyr" (EDRPOU code 25923929)
  • Membership in Editorial Board:
  • - International Journal of Advanced Research in Mathematics, Switzerland, Editorial Board Member
  • - Seminar Series in Mathematics and Computer Science (SSMCS), Romania, Editorial Board Member
  • 2007 – 2009 - Grant 25.1/084 DFFD
  • 2012 – 2015 - Grant from the Ministry of Education, Youth and Sports of Ukraine
  • 2013 - Prize of the Verkhovna Rada of Ukraine for Young Scientists
  • 2015 – 2017 - Scholarship of the National Academy of Sciences of Ukraine for young scientists
  • 2015 – 2018 - Grant from the Ministry of Education and Science of Ukraine
  • 2018 - Prize of the Institute of Mathematics of the National Academy of Sciences of Ukraine named after O. Yu. Ishlinskyi for young scientists
  • 2018 – 2020 - Joint Ukrainian-Polish grant “Analogs of complex analysis in differential equations, geometry and physical applications”
  • 2020 – 2021 - Grant of the NAS of Ukraine for research groups of young scientists (State registration number: 0120U100222)
  • 2022 - Prize of the President of Ukraine for Young Scientists
  • 2024 - Scholarship of the President of Ukraine for young scientists
  • 2024 - Grant of the National Academy of Sciences of Ukraine for research groups of young scientists (State registration number: 0125U001337)