Борислав Радков Драганов

Борислав Радков Драганов

Доцент
Доктор
Имейл: 
bdraganov(at)fmi.uni-sofia.bg
Телефон: 
02/8161-766
Кабинет: 
ФМИ-211
Приемно време: 

петък 14 –16
или по предварителна уговорка

Образование и научни степени

  • 2004: доктор, СУ "Св. Кл. Охридски", ФМИ
  • 1998: магистър специалност математика, СУ "Св. Кл. Охридски", ФМИ
  • 1993: Първа английска езикова гимназия, гр. София

Научни интереси

  • Теория на апроксимациите
  • Функционален анализ
  • Хармоничен анализ

Преподавателска дейност

Списък с публикации

  1. A new modulus of smoothness for trigonometric polynomial approximation, East J. Approx. 8 (2002), 4, 465-499 (pdf).
  2. A new modulus of smoothness for trigonometric polynomial approximation,  Constructive Theory of Functions, Varna, 2002. Proc. Ed. B. Bojanov, Darba, Sofia, 2003, 245-250 (pdf).
  3. The trigonometric analogue of the Taylor's formula and its application, Annuaire Univ. Sofia Fac. Math. Inform.  96 (2004), 141-154 (pdf).
  4. (with Kamen G. Ivanov) A new characterization of weighted Peetre K-functionals, Constr. Approx. 21 (2005), 113-148 (pdf, original publication available at Springer http://www.springerlink.com/).
  5. (with Kamen G. Ivanov) A Characterization of Weighted Lp Approximations by the Gamma and the Post-Widder Operators, Proc. intern. conf. "Constructive Theory of Functions, Varna 2005'', Ed. B. Bojanov, Marin Drinov Academic Publishing House, Sofia, 2006, 80-87 (pdf).
  6. (with Kamen G. Ivanov) Characterizations of Weighted K-Functionals and Their Application, Proc. intern. conf. "Constructive Theory of Functions, Varna 2005'', Ed. B. Bojanov, Marin Drinov Academic Publishing House, Sofia, 2006, 88-97 (pdf).
  7. (with Kamen G. Ivanov) A new characterization of weighted Peetre K-functionals (II), Serdica Math. J. 33 (2007), 59-124 (pdf).
  8. (with Kamen G. Ivanov) A characterization of weighted approximations by the Post-Widder and the Gamma operators, J. Approx. Theory 146 (2007), 3-27 (preprintoriginal publication available at Elsevier).
  9. (with Kamen G. Ivanov) Equivalence between K-functionals based on continuous linear transforms, Serdica Math. J. 33 (2007), 475-494 (pdf).
  10. Simultaneous approximation of functions by Fejér-type operators in a generalized Hölder norm, East J. Approx. 14 (2008), 439-449 (pdf).
  11. Exact estimates of the rate of approximation of convolution operators, J. Approx. Theory 162 (2010), 952-979 (preprint, original publication available at Elsevier).
  12. (with Kamen G. Ivanov) A Characterization of Weighted Approximations by the Post-Widder and the Gamma Operators (II), J. Approx. Theory 162 (2010), 1805-1851 (preprint, original publication available at Elsevier).
  13. On the approximation by convolution operators in homogeneous Banach spaces of periodic functions, Math. Balkanica 25 (2011), 39-59 (pdf).
  14. (with Parvan E. Parvanov) On estimating the rate of best trigonometric approximation by a modulus of smoothness, Acta Math. Hungar. 131 (2011),  360-379 (pdf, original publication available at Springer http://www.springerlink.com).
  15. Estimating the rate of best trigonometric approximation in homogeneous Banach spaces by moduli of smoothness, Proc. intern. conf. "Constructive Theory of Functions", Sozopol 2010: In Memory of Borislav Bojanov, Eds. G. Nikolov and R. Uluchev, Marin Drinov Academic Publishing House, Sofia, 2012, 80-92 (pdf). 
  16. An improved Jackson inequality for best trigonometric approximation, Ukr. Mat. Zhurn.  65 (2013), 1219-1226 and Ukrainian Math. J. 65 (2014), 1354-1362 (pdf, final publication available at link.springer.com); a preprint: A sharp Jackson inequality for best trigonometric approximation, CRM Preprint Series 1101, 2012 (available at CRM).

  17. Upper estimates of the approximation rate of combinations of iterates of the Bernstein operator, Annuaire Univ. Sofia Fac. Math. Inform. 101 (2013), 95-104 (pdf).
  18. (with Kamen G. Ivanov) A generalized modulus of smoothness, Proc. Amer. Math. Soc. 142 (2014), 1577-1590.  
  19. On simultaneous approximation by iterated Boolean sums of Bernstein operators, Results Math. 66 (2014), 21-41 (read-only pdf at Springer Nature SharedIt, pdf, final publication available at link.springer.com). 
  20. (with Kamen G. Ivanov) Natural weights for uniform approximation by the Szasz-Mirakjan operator,  Proc. intern. conf. "Constructive Theory of Functions", Sozopol 2013: Dedicated to Blagovest Sendov and to the memory of Vasil Popov, Eds. Kamen Ivanov, Geno Nikolov and Rumen Uluchev, Prof. Marin Drinov Academic Publishing House, Sofia, 2014, 57-82 (pdf).
  21. On the approximation by convolution operators in homogeneous Banach spaces on Rd, Math. Balkanica  28 (2014), 9-36 (pdf).
  22. Strong estimates of the weighted simultaneous approximation by the Bernstein and Kantorovich operators and their iterated Boolean sums, J. Approx. Theory  200 (2015), 92–135 (accepted paper, original publication available at Elsevier).
  23. (with Ivan Gadjev) Direct and converse Voronovskaya estimates for the Bernstein operator, Results Math. 73:11 (2018) (read-only pdf at Springer Nature SharedIt, final publication available at link.springer.com).
  24. (with Kamen G. Ivanov) A New Characterization of Weighted Peetre K-Functionals (III), Proc. intern. conf. "Constructive Theory of Functions", Sozopol 2016, Eds. Kamen Ivanov, Geno Nikolov and Rumen Uluchev, Prof. Marin Drinov Academic Publishing House, Sofia (to appear).
  25. An exact strong converse inequality for the weighted simultaneous approximation by the Bernstein operator, Proc. intern. conf. "Constructive Theory of Functions", Sozopol 2016, Eds. Kamen Ivanov, Geno Nikolov and Rumen Uluchev, Prof. Marin Drinov Academic Publishing House, Sofia (to appear).