# Publications of Assoc. Prof. Borislav Draganov, Ph. D.

Note: Preprints and pdf's are available here.

- A new modulus of smoothness for trigonometric polynomial approximation,
*East J. Approx.***8**(2002), 4, 465-499. - A new modulus of smoothness for trigonometric polynomial approximation, Constructive Theory of Functions, Varna, 2002. Proc. Ed. B. Bojanov, Darba, Sofia, 2003, 245-250.
- The trigonometric analogue of the Taylor's formula and its application,
*Annuaire Univ. Sofia Fac. Math. Inform.***96**(2004), 141-154. - (with Kamen G. Ivanov) A new characterization of weighted Peetre
*K*-functionals,*Constr. Approx.***21**(2005), 113-148. - (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. - (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. - (with Kamen G. Ivanov) A new characterization of weighted Peetre
*K*-functionals (II),*Serdica Math. J.***33**(2007), 59-124. - (with Kamen G. Ivanov) A characterization of weighted approximations by the Post-Widder and the Gamma operators,
*J. Approx. Theory***146**(2007), 3-27. - (with Kamen G. Ivanov) Equivalence between
*K*-functionals based on continuous linear transforms,*Serdica Math. J*.**33**(2007), 475-494. - Simultaneous approximation of functions by Fejér-type operators in a generalized Hölder norm,
*East J. Approx.***14**(2008), 439-449. - Exact estimates of the rate of approximation of convolution operators,
*J. Approx. Theory***162**(2010), 952-979. - (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*.* - On the approximation by convolution operators in homogeneous Banach

spaces of periodic functions,*Math. Balkanica***25**(2011), 39-59. - (with Parvan E. Parvanov) On estimating the rate of best trigonometric approximation by a modulus of smoothness,
*Acta Math. Hungar.***131**(2011), 360-379. - 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.
- An improved Jackson inequality for best trigonometric approximation,
*Ukr. Mat. Zhurn.***65**(2013) and*Ukrainian Math. J*.**65**(2014), 1354-1362, 1219-1226; a preprint: A sharp Jackson inequality for best trigonometric approximation,*CRM Preprint Series***1101**, 2012. - Upper estimates of the approximation rate of combinations of iterates of the Bernstein operator,
*Annuaire Univ. Sofia Fac. Math. Inform.***101**(2013), 95-104. - (with Kamen G. Ivanov)
A generalized modulus of smoothness,
*Proc. Amer. Math. Soc.***142**(2014), 1577-1590. - On simultaneous approximation by iterated Boolean sums of Bernstein operators,
*Results Math.***66**(2014), 21-41. - (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.
- On the approximation by convolution operators in homogeneous Banach spaces on R^d, Math. Balkanica 28 (2014), 9-36
- 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.