Yanchenko Sergii
Education
01.09.2020 – 31.08.2022: Post-doctoral studying at Institute of Mathematics of National Academy of Sciences of Ukraine, Department of Theorey of functions, Kyiv; Scientific consultant: Dr. Prof. Romanyuk A.S.
01.11.2007 – 31.10.2010 - PhD student at the Institute of Mathematics of NAS of Ukraine, Kyiv, Department of Theory of Functions. Supervisor: Dr. Prof. Romanyuk A.S.
2005 - 2006 Student at Ternopil Volodymyr Hnatyuk National Pedagogical University, Faculty of Physics and Mathematics, master's degree with honours.
2001 - 2005 Student at Ternopil Volodymyr Hnatyuk National Pedagogical University, Faculty of Physics and Mathematics, bachelor degree with honours.
01.11.2007 – 31.10.2010 - PhD student at the Institute of Mathematics of NAS of Ukraine, Kyiv, Department of Theory of Functions. Supervisor: Dr. Prof. Romanyuk A.S.
2005 - 2006 Student at Ternopil Volodymyr Hnatyuk National Pedagogical University, Faculty of Physics and Mathematics, master's degree with honours.
2001 - 2005 Student at Ternopil Volodymyr Hnatyuk National Pedagogical University, Faculty of Physics and Mathematics, bachelor degree with honours.
Dissertations
PhD thesis: "Investigation of approximative characteristics of classes of functions of several variables"
01.01.01 - mathematical analysis
Institute of Mathematics of NAS of Ukraine, Kyiv
Date of defence: 05.04.2011
Supervisor: Prof. Dr. Romanyuk A.S.
01.01.01 - mathematical analysis
Institute of Mathematics of NAS of Ukraine, Kyiv
Date of defence: 05.04.2011
Supervisor: Prof. Dr. Romanyuk A.S.
Research interests
- Approximation of functions of real variable;
- Functional spaces.
- Functional spaces.
Experience
01.02.2018 - till now: Senior researcher, Institute of Mathematics of NAS of Ukraine, Kyiv, Department of Theory of Functions.
25.03.2014 - 31.01.2018: Researcher, Institute of Mathematics of NAS of Ukraine, Kyiv, Department of Theory of Functions.
01.11.2010 - 24.03.2014: Junior Researcher, Institute of Mathematics of NAS of Ukraine, Kyiv, Department of Theory of Functions.
1.09.2006 - 30.10.2007 – Lecturer at the Department of Computer Technology of Halytskyi Institute named after Vyacheslav Chornovil, Ternopil.
25.03.2014 - 31.01.2018: Researcher, Institute of Mathematics of NAS of Ukraine, Kyiv, Department of Theory of Functions.
01.11.2010 - 24.03.2014: Junior Researcher, Institute of Mathematics of NAS of Ukraine, Kyiv, Department of Theory of Functions.
1.09.2006 - 30.10.2007 – Lecturer at the Department of Computer Technology of Halytskyi Institute named after Vyacheslav Chornovil, Ternopil.
Talks on conferences
— Kolmogorov widths and entropy numbers of the classes of periodic functions of many variables with dominating mixed smoothness. Workshop «From Modeling and Analysis to Approximation and Fast Algorithms»; University of Luebeck; Hasenwinkel, Germany, September 02-06, 2023. (with A.S.Romanyuk)
https://www.math.uni-luebeck.de/mitarbeiter/prestin/workshop/hasenwinkel2023-VW/
— Estimates of approximating characteristics for the classes of periodic functions in the space $B_{1,1}$. International Workshop "Current Trends in Analysis and Approximation Theory", July 18, 2023, the International Telematic University UNINETTUNO, Roma, Italy: Book of Proceedings. 2023, P.30-31. (with A.S.Romanyuk)
https://sites.google.com/uninettunouniversity.net/ctaat/home
— Best orthogonal trigonometric approximations for classes of periodic functions with a dominating mixed smoothness. International Conference «Theory of Approximation of Functions and its Applications», dedicated to the 80th anniversary of Corresponding Member of the National Academy of Sciences of Ukraine, Professor Alexander STEPANETS (1942-2007). Institute of Mathematics of the NAS of Ukraine; Lesya Ukrainka Volyn National University. Lutsk, Ukraine, June 6–10, 2022. (with A.S.Romanyuk)
https://sites.google.com/view/tafa-2022en
— Entropy numbers of the Nikol’skii–Besov classes in the space of quasi-continuous functions // International Conference Mathematical Analysis, Differential Equation & Applications (MADEA-9), Kyrgyz-Turkish Manas University, Bishkek, Kyrgyz Republic, June 21-25. Abstracts – Bishkek: KTMU. 2021. – P. 65-66. (with A.S.Romanyuk)(Online)
http://madea2021.manas.edu.kg/en
— Estimates for the entropy numbers of the Nikol'skii-Besov classes in the space of quasi-continuous functions // International Online Workshop on Approximation Theory, March 19-21, 2021, Ivano-Frankivsk, Ukraine: ABSTRACTS. – P. 29-30. (with A.S.Romanyuk) (Online)
https://conference.pnu.edu.ua/iowat/en/home/
— Best approximation of functions from anisotropic Nikol’skii-Besov classes // International Conference of Young Mathematicians dedicated to the 100th Anniversary of Academician of National Academy of Sciences of Ukraine, Professor Yu.O.Mitropolskiy (1917–2008). June 7–10, 2017, Kyiv, Ukraine. Abstracts. — Kyiv: Institute of Mathematics of NAS of Ukraine, 2017. — P. 100.
https://www.imath.kiev.ua/~young/conf2/index.php?module=1&lang=en
— Approximation of functions from the isotropic Nikol'skii-Besov classes. AMMODIT and final EUMLS Workshop "Mathematics for Life Sciences". Hasenwinkel, March 7—11, 2016.
http://www.math.uni-luebeck.de/EUMLS-AMMODIT2016/
— Approximation of functions from the isotropic Nikol'skii-Besov classes. Third conference. «Mathematics for Life Sciences». Rivne, September 15—19, 2015.
http://eumls2015.humboldt.org.ua/
— Approximation of the Nikol'skii-Besov classes with dominating mixed smoothness by entire functions of a spacial form. Mecklenburg Workshop "Approximation Methods and Function Spaces". Hasenwinkel, March 16—20, 2015.
http://www.math.uni-luebeck.de/workshop/hasenwinkel2015.php
— Approximations of classes $B^{r}_{p,\theta}$ of functions of many variables in the space $L_q(\mathbb{R}^d)$. International conference "Modern problems of analysis, the 70 th anniversary of the department of mathematical analysis Chernivtsi University, September 30 — October 3, 2010.
— Approximations of functions with Besov classes by entire function. International Conference "Approximation Theory and Applications", in memory of N.P.Korneichuk, Dnepropetrovsk, 14—17 June, 2010.
— Approximations of functions of many variables with classes $S^r_{p,\theta}B(\mathbb{R}^d)$ by entire function. International Workshop "Approximation Theory", St. Petersburg, Russia, May 6 — 8, 2010.
— Approximations of classes functions of many variables in the space by entire function in the space $L_p(\mathbb{R}^d)$. Conference "Functional Methods in Approximation Theory and Operator Theory III", dedicated to the memory of V. K. Dzyadyk (1919-1998), Svityaz, Ukraine, August 22 — 26, 2009.
— Approximations of classes functions of many variables in the space $L_q(\mathbb{R}^d)$. International Conference "Analytic methods of mechanics and complex analysis" dedicated to N.A.Kilchevskii and V.A.Zmorovich on the occasion of their birthday centenary, Kiev, 29 June — 5 July, 2009.
— Approximations of the classes $B^{\Omega}_{p,\theta}$ functions of many variables in the space $L_q(\mathbb{R}^d)$. International Conference "Modern problems of mathematics, mechanics and their application" on the 70-th anniversary of MSU Rector Academician V.A.Sadovnichy, 30 March - 2 April 2009, Moscow, Russia.
— Best approximations of the classes $B^{\Omega}_{p,\theta}$ of functions of many variables in the space $L_q(\mathbb{R}^d)$. International Conference "Differential Equations, Theory of Functions and their Application", Melitopol, Ukraine, June 6 - 8, 2008.
https://www.math.uni-luebeck.de/mitarbeiter/prestin/workshop/hasenwinkel2023-VW/
— Estimates of approximating characteristics for the classes of periodic functions in the space $B_{1,1}$. International Workshop "Current Trends in Analysis and Approximation Theory", July 18, 2023, the International Telematic University UNINETTUNO, Roma, Italy: Book of Proceedings. 2023, P.30-31. (with A.S.Romanyuk)
https://sites.google.com/uninettunouniversity.net/ctaat/home
— Best orthogonal trigonometric approximations for classes of periodic functions with a dominating mixed smoothness. International Conference «Theory of Approximation of Functions and its Applications», dedicated to the 80th anniversary of Corresponding Member of the National Academy of Sciences of Ukraine, Professor Alexander STEPANETS (1942-2007). Institute of Mathematics of the NAS of Ukraine; Lesya Ukrainka Volyn National University. Lutsk, Ukraine, June 6–10, 2022. (with A.S.Romanyuk)
https://sites.google.com/view/tafa-2022en
— Entropy numbers of the Nikol’skii–Besov classes in the space of quasi-continuous functions // International Conference Mathematical Analysis, Differential Equation & Applications (MADEA-9), Kyrgyz-Turkish Manas University, Bishkek, Kyrgyz Republic, June 21-25. Abstracts – Bishkek: KTMU. 2021. – P. 65-66. (with A.S.Romanyuk)(Online)
http://madea2021.manas.edu.kg/en
— Estimates for the entropy numbers of the Nikol'skii-Besov classes in the space of quasi-continuous functions // International Online Workshop on Approximation Theory, March 19-21, 2021, Ivano-Frankivsk, Ukraine: ABSTRACTS. – P. 29-30. (with A.S.Romanyuk) (Online)
https://conference.pnu.edu.ua/iowat/en/home/
— Best approximation of functions from anisotropic Nikol’skii-Besov classes // International Conference of Young Mathematicians dedicated to the 100th Anniversary of Academician of National Academy of Sciences of Ukraine, Professor Yu.O.Mitropolskiy (1917–2008). June 7–10, 2017, Kyiv, Ukraine. Abstracts. — Kyiv: Institute of Mathematics of NAS of Ukraine, 2017. — P. 100.
https://www.imath.kiev.ua/~young/conf2/index.php?module=1&lang=en
— Approximation of functions from the isotropic Nikol'skii-Besov classes. AMMODIT and final EUMLS Workshop "Mathematics for Life Sciences". Hasenwinkel, March 7—11, 2016.
http://www.math.uni-luebeck.de/EUMLS-AMMODIT2016/
— Approximation of functions from the isotropic Nikol'skii-Besov classes. Third conference. «Mathematics for Life Sciences». Rivne, September 15—19, 2015.
http://eumls2015.humboldt.org.ua/
— Approximation of the Nikol'skii-Besov classes with dominating mixed smoothness by entire functions of a spacial form. Mecklenburg Workshop "Approximation Methods and Function Spaces". Hasenwinkel, March 16—20, 2015.
http://www.math.uni-luebeck.de/workshop/hasenwinkel2015.php
— Approximations of classes $B^{r}_{p,\theta}$ of functions of many variables in the space $L_q(\mathbb{R}^d)$. International conference "Modern problems of analysis, the 70 th anniversary of the department of mathematical analysis Chernivtsi University, September 30 — October 3, 2010.
— Approximations of functions with Besov classes by entire function. International Conference "Approximation Theory and Applications", in memory of N.P.Korneichuk, Dnepropetrovsk, 14—17 June, 2010.
— Approximations of functions of many variables with classes $S^r_{p,\theta}B(\mathbb{R}^d)$ by entire function. International Workshop "Approximation Theory", St. Petersburg, Russia, May 6 — 8, 2010.
— Approximations of classes functions of many variables in the space by entire function in the space $L_p(\mathbb{R}^d)$. Conference "Functional Methods in Approximation Theory and Operator Theory III", dedicated to the memory of V. K. Dzyadyk (1919-1998), Svityaz, Ukraine, August 22 — 26, 2009.
— Approximations of classes functions of many variables in the space $L_q(\mathbb{R}^d)$. International Conference "Analytic methods of mechanics and complex analysis" dedicated to N.A.Kilchevskii and V.A.Zmorovich on the occasion of their birthday centenary, Kiev, 29 June — 5 July, 2009.
— Approximations of the classes $B^{\Omega}_{p,\theta}$ functions of many variables in the space $L_q(\mathbb{R}^d)$. International Conference "Modern problems of mathematics, mechanics and their application" on the 70-th anniversary of MSU Rector Academician V.A.Sadovnichy, 30 March - 2 April 2009, Moscow, Russia.
— Best approximations of the classes $B^{\Omega}_{p,\theta}$ of functions of many variables in the space $L_q(\mathbb{R}^d)$. International Conference "Differential Equations, Theory of Functions and their Application", Melitopol, Ukraine, June 6 - 8, 2008.
Miscellaneous
Award of President of Ukraine for young scientists (2021) for work «Extremal problems of approximation of classes of functions of one and several variables», the team consisting of Yanchenko S.Ya., Pozharska K.V., Stepaniuk T.A.
Decree of the President of Ukraine
Award of the Verkhovna Rada of Ukraine to the most talented young scientists in the field of fundamental and applied research and scientific and technical developments in 2012.
May 2016 - April 2018, scholarship of the President of Ukraine for young scientists;
May 2014 - April 2016, scholarship of the NAS of Ukraine for young scientists.
2015 - 2019: Chairman of the Council of Young Scientists of the Institute of Mathematics of NAS of Ukraine.
2016 - 2018: Chairman of the Council of Young Scientists of the Department of Mathematics of NAS of Ukraine.
2016 - 2019: a member of the Council of Young Scientists of NAS of Ukraine.
$\normalsize{\textbf{Scientific Projects:}}$
• Scientific researcher in the international project “From Modeling and Analysis to Approximation” No. 645672, coordinating institution: University of Lübeck (Germany), 11.2020-12.2023, funding source: Volkswagen-Stiftung.
Project web page
• Scientific researcher of the project F84/177-2019 "Constructive methods of analysis of boundary value problems and restoration of functions"; period of implementation: 10.2019-12.2019; grant of the President of Ukraine to doctors of science for scientific research in 2019.
• Scientific researcher of the SRW "Evolutionary boundary-value problems and approximate properties of functional sets and their applications", grant from the National Academy of Sciences of Ukraine to the research group of young scientists of the National Academy of Sciences of Ukraine to conduct research in the priority areas of development of science and technology in 2018-2019.
• 2014-2016: Researcher in the project “EU-Ukrainian Mathematicians for Life Sciences” funded by Marie Curie Actions - International Research Staff Exchange Scheme (IRSES) FP7-People-2011-IRSES, Project number 295164. (Project web page)
Research visits:
1) 15.02.2014 - 15.04.2014 - Institute of Mathematics, Universität zu Lübeck, Lübeck, Germany, Prof. Dr. Jürgen Prestin;
2) 21.10.2014 - 23.11.2014 - Institute of Mathematics, Universität zu Lübeck, Lübeck, Germany, Prof. Dr. Jürgen Prestin;
3) 05.03.2015 - 30.03.2015 - Institute of Mathematics, Universität zu Lübeck, Lübeck, Germany, Prof. Dr. Jürgen Prestin.
*****
Orcid ID
Scopus perconal web page
Mathscinet perconal web page
Google Scholar perconal web page
Decree of the President of Ukraine
Award of the Verkhovna Rada of Ukraine to the most talented young scientists in the field of fundamental and applied research and scientific and technical developments in 2012.
May 2016 - April 2018, scholarship of the President of Ukraine for young scientists;
May 2014 - April 2016, scholarship of the NAS of Ukraine for young scientists.
2015 - 2019: Chairman of the Council of Young Scientists of the Institute of Mathematics of NAS of Ukraine.
2016 - 2018: Chairman of the Council of Young Scientists of the Department of Mathematics of NAS of Ukraine.
2016 - 2019: a member of the Council of Young Scientists of NAS of Ukraine.
$\normalsize{\textbf{Scientific Projects:}}$
• Scientific researcher in the international project “From Modeling and Analysis to Approximation” No. 645672, coordinating institution: University of Lübeck (Germany), 11.2020-12.2023, funding source: Volkswagen-Stiftung.
Project web page
• Scientific researcher of the project F84/177-2019 "Constructive methods of analysis of boundary value problems and restoration of functions"; period of implementation: 10.2019-12.2019; grant of the President of Ukraine to doctors of science for scientific research in 2019.
• Scientific researcher of the SRW "Evolutionary boundary-value problems and approximate properties of functional sets and their applications", grant from the National Academy of Sciences of Ukraine to the research group of young scientists of the National Academy of Sciences of Ukraine to conduct research in the priority areas of development of science and technology in 2018-2019.
• 2014-2016: Researcher in the project “EU-Ukrainian Mathematicians for Life Sciences” funded by Marie Curie Actions - International Research Staff Exchange Scheme (IRSES) FP7-People-2011-IRSES, Project number 295164. (Project web page)
Research visits:
1) 15.02.2014 - 15.04.2014 - Institute of Mathematics, Universität zu Lübeck, Lübeck, Germany, Prof. Dr. Jürgen Prestin;
2) 21.10.2014 - 23.11.2014 - Institute of Mathematics, Universität zu Lübeck, Lübeck, Germany, Prof. Dr. Jürgen Prestin;
3) 05.03.2015 - 30.03.2015 - Institute of Mathematics, Universität zu Lübeck, Lübeck, Germany, Prof. Dr. Jürgen Prestin.
*****
Orcid ID
Scopus perconal web page
Mathscinet perconal web page
Google Scholar perconal web page