The Main Publications by A.I.STEPANETS
  1. Stepanets, A. I.
    Extremal problems for number series. (Ukrainian) Dopov. Nats. Akad. Nauk Ukr. Mat. Prirodozn. Tekh. Nauki (2006), no. 7, 31-37.
    MR2312489
  2. Stepanets, A. I.
    Problems in approximation theory in linear spaces. (Russian) Ukrain. Mat. Zh. 58 (2006), no. 1, 54-102.
    MR2007c:41027
  3. Stepanets, A. I.
    Methods of Approximation Theory. Leiden: VSP, 2005. - 919 pp.
    MR2007c:42001
  4. Stepanets, A. I.; Shidlich, A. L.
    On an extremal problem for positive series. (Ukrainian) Ukrain. Mat. Zh. 57 (2005), no. 12, 1968-1976.
    MR2007h:41034
  5. Stepanets, A. I.
    Best $n$-term approximations with restrictions. Ukrainian. Math. J. 57 (2005), no. 1, 640-665.
    MR2006h:41021
  6. Stepanets, A. I.
    Best approximations of $q$-ellipsoids in the spaces $S\sp {p,µ}\sb {\phi}$. Ukrainian. Math. J. 56 (2004), no. 10, 1646-1652.
    MR2006a:41038
  7. Stepanets, A. I.; Sokolenko, I. V.
    Approximation of $\overline\psi$-integrals of functions defined on the real line by Fourier operators. Ukrainian. Math. J. 56 (2004), no. 7, 1144-1150.
    MR2005h:42004
  8. Stepanets, A. I.; Shidlich, A. L.
    Best $n$-term approximations by $\Lambda$-methods in the spaces $S\sp p\sb \phi$. Ukrainian. Math. J. 55 (2003), no. 8, 1338-1362.
    MR2005d:41047
  9. Stepanets, A. I.
    Extremal problems of approximation theory in linear spaces. Ukrainian. Math. J. 55 (2003), no. 10, 1662-1698.
    MR2006d:41041
  10. Stepanets, A. I.; Rukasov V. I.
    Best "continuous" $n$-term approximations in the spaces $S\sp p\sb \phi$. Ukrainian. Math. J. 55 (2003), no. 5, 801-811.
    MR2004k:41053
  11. Stepanets, A. I.; Rukasov V. I.
    The spaces $S\sp p$ with a nonsymmetric metric. Ukrainian. Math. J. 55 (2003), no. 2, 322-338.
    MR2004k:41053
  12. Stepanets, A. I.
    Approximation characteristics of the spaces $S\sp p$. (Russian). Ukrainian Mathematics Congress. - Nats. Akad. Nauk Ukraini, Inst. Mat., Kiev, 2002. , 208-226.
  13. Stepanets, A. I.; Rukasov V. I.
    Approximation properties of the de la Vallee Poussin method. Ukrainian. Math. J. 54 (2002), no. 2, 1324-1354.
    MR2004h:42005
  14. Stepanets, A. I.
    Methods of Approximation Theory: In 2 parts. (Russian) Kiev: Inst. Mat. Nats. Akad. Nauk Ukrain. 2002. - Part I. - 427 pp.
  15. Stepanets, A. I.
    Methods of Approximation Theory: In 2 parts. (Russian) Kiev: Inst. Mat. Nats. Akad. Nauk Ukrain. 2002. - Part II. - 468 pp.
  16. Stepanets, A. I.; Savchuk, V. V.
    Approximations of Cauchy-type integrals. (Russian) Ukrain. Mat. Zh. 54 (2002), no. 5, 706-740.
  17. Stepanets, A. I.
    Approximation of convolution classes by Fourier sums: new results. (Ukrainian) Ukrain. Mat. Zh. 54 (2002), no. 5, 581-602.
  18. Stepanets, A. I.; Serdyuk, A. S.
    Direct and inverse theorems in the theory of the approximation of functions in the space Sp. (Russian) Ukrain. Mat. Zh. 54 (2002), no. 1, 106-124.; translation in Ukrainian Math. J. 54 (2002), no. 1, 126-148.
  19. Stepanets, A. I.
    Approximation characteristics of the spaces Sp. (Russian) Nats. Akad. Nauk Ukrain. Inst. Mat. Preprint 2001, no. 2, 86 pp.
    MR2003c:41036
  20. Stepanets, A. I.
    Approximation characteristics of the spaces Sp in various metrics. (Russian) Ukrain. Mat. Zh. 53 (2001), no. 8, 1121--1146.
    MR2003b:41030
  21. Stepanets, A. I.
    Solution of the Kolmogorov-Nikolsky problem for Poisson integrals of continuous functions. (Russian) Mat. Sb. 192 (2001), no. 1, 113--138; translation in Sb. Math. 192 (2001), no. 1-2, 113--139
    MR 2002f:41009
  22. Stepanets, A. I.
    Approximation characteristics of the spaces Sp (Russian) Ukrain. Mat. Zh. 53 (2001), no. 3, 392--416; translation in Ukrainian Math. J. 53 (2001), no. 3, 446--475
  23. Stepanets, A. I.
    Approximative characteristics of spaces Sp. (Russian. English abstract) Nats. Akad. Nauk Ukrain. Inst. Mat. Preprint 2000, no. 2, 1--52.
  24. Stepanets, A. I.; Serdyuk, A. S.
    Approximation of periodic analytic functions by interpolation trigonometric polynomials. (Russian) Ukrain. Mat. Zh. 52 (2000), no. 12, 1689--1701; translation in Ukrainian Math. J. 52 (2000), no. 12, 1928--1941 (2001)
    MR2002d:42003
  25. Stepanets, A. I.
    Approximation characteristics of the spaces Sp. (Russian) Ukrain. Mat. Zh. 53 (2001), no. 3, 392--416; translation in Ukrainian Math. J. 53 (2001), no. 3, 446--475
    MR 2002d:41035
  26. Stepanets, A. I.; Serdyuk, A. S.
    Lebesgue inequalities for Poisson integrals. (Russian) Ukrain. Mat. Zh. 52 (2000), no. 6, 798--808; translation in Ukrainian Math. J. 52 (2000), no. 6, 914--925 (2001)
    MR 2002c:42003
  27. Stepanets, A. I.
    Solution of the Kolmogorov-Nikolsky problem for Poisson integrals of continuous functions. (Russian) Nats. Akad. Nauk Ukrain. Inst. Mat. Preprint 2000, no. 1, 1--42.
    MR 2002c:42002
  28. Stepanets, A. I.; Serdyuk, A. S.
    Lebesgue inequalities for Poisson integrals. (Russian) Nats. Akad. Nauk Ukrain. Inst. Mat. Preprint 2000, no. 1, 43--59
    MR 2002b:42006
  29. Stepanets, A. I.; Serdyuk, A. S.
    Estimation of the remainder of approximation by trigonometric polynomials on the classes of infinitely differentiable functions. (Ukrainian) Proceedings of the Institute of Mathematics of National Academy of Sciences of Ukraine Vol.31 (2000), 447--460.
  30. Stepanets, A. I.; Serdyuk, A. S. Approximation by Fourier sums and best approximations on classes of analytic functions. (Russian) Nats. Akad. Nauk Ukrain. Inst. Mat. Preprint 2000, no. 1, 60--92
    MR 2001m:42006
  31. Stepanets, A. I.
    Approximation of -integrals of periodic functions by Fourier sums (small smoothness). II. (Russian) Ukrain. Mat. Zh. 50 (1998), no. 3, 388--400.
    MR 2001g:42006
  32. Stepanets, A. I.
    Approximation of -integrals of periodic functions by Fourier sums (small smoothness). I. (Russian) Ukrain. Mat. Zh. 50 (1998), no. 2, 274--291.
    MR 2001g:42005
  33. Stepanets, A. I.
    The rate of convergence of a group of deviations on sets of -integrals. (Russian) Ukrain. Mat. Zh. 51 (1999), no. 12, 1673--1693; translation in Ukrainian Math. J. 51 (1999), no. 12, 1892--1916 (2000)
    MR 2001a:42005
  34. Stepanets, A.; Wang, Kunyang; Zhang, Xirong
    Approximation of locally integrable functions on the real line. Ukrain. Mat. Zh. 51 (1999), no. 11, 1549--1561.
    MR 2000m:41032
  35. Stepanets, A. I.
    Approximation properties of the Zygmund method. (Russian) Ukrain. Mat. Zh. 51 (1999), no. 4, 493--518; translation in Ukrainian Math. J. 51 (1999), no. 4, 546--576
    MR 2000m:42007
  36. Stepanets, A. I.
    Some statements for convex functions. (Russian) Ukrain. Mat. Zh. 51 (1999), no. 5, 688--702; translation in Ukrainian Math. J. 51 (1999), no. 5, 764--780 (2000)
    MR 2000h:26019
  37. Stepanets, A. I.
    The rate of convergence of Fourier series on classes of -integrals. (Russian) Ukrain. Mat. Zh. 49 (1997), no. 8, 1069--1113; translation in Ukrainian Math. J. 49 (1997), no. 8, 1201--1251 (1998)
    MR 99e:42002
  38. Stepanets, A. I.
    Approximation of -integrals of periodic functions by Fourier sums (small smoothness). (Russian) Nats. Akad. Nauk Ukrain. Inst. Mat. Preprint 1997, no. 3, 48 pp.
    MR 98j:42004
  39. Stepanets, A. I.
    Approximations in spaces of locally integrable functions. Ukrainian Math. J. 46 (1994), no. 5, 638--670 (1995).
    MR97i:42004
  40. Stepanets, A. I.; Stepanets, N. I.
    Approximation of -integrals of periodic functions by Fourier sums in the space L. (Russian) Rate of convergence of Fourier series on convolution classes (Russian). Nats. Akad. Nauk Ukrain. Inst. Mat. Preprint 1996, no. 11, ii, 63--69.
    MR 97h:42002b
  41. Stepanets, A. I.
    Approximation of -integrals of periodic functions by Fourier sums. (Russian) Rate of convergence of Fourier series on convolution classes (Russian). Nats. Akad. Nauk Ukrain. Inst. Mat. Preprint 1996, no. 11, ii, 3--62.
    MR 97h:42002a
  42. Stepanets, A. I.; Lasuriya, R. A.
    Strong summability of orthogonal expansions of summable functions. II. (Russian) Ukrain. Mat. Zh. 48 (1996), no. 3, 393--405.
    MR 97g:42032b
  43. Stepanets, A. I.; Lasuriya, R. A.
    Strong summability of orthogonal expansions of summable functions. I. (Russian) Ukrain. Mat. Zh. 48 (1996), no. 2, 260--277.
    MR 97g:42032a
  44. Stepanets, A. I.
    Inverse theorems for the approximation of periodic functions. (Russian) Ukrain. Mat. Zh. 47 (1995), no. 9, 1266--1273; translation in Ukrainian Math. J. 47 (1995), no. 9, 1441--1448 (1996)
    MR 97c:42005
  45. Stepanets, A. I.; Serdyuk, A. S.
    Lower bounds for the widths of classes of convolution s of periodic functions in C and L metrics. (Russian) Ukrain. Mat. Zh. 47 (1995), no. 8, 1112--1121.
    MR 96m:41044
  46. Stepanets, Alexander I.
    Classification and approximation of periodic functions. Translated from the 1987 Russian original by P. V. Malyshev and D. V. Malyshev and revised by the author. Mathematics and its Applications, 333. Kluwer Academic Publishers Group, Dordrecht, 1995. x+360 pp. ISBN: 0-7923-3603-8
    MR 96h:42003
  47. Stepanets, A. I.; Serdyuk, A. S.
    On the existence of interpolation SK-splines. (Russian) Ukrain. Mat. Zh. 46 (1994), no. 11, 1546--1553.
    MR 96g:41010
  48. Stepanets, A. I.
    Approximation of Cauchy-type integrals in Jordan domains. (Russian) Ukrain. Mat. Zh. 45 (1993), no. 6, 809--833; translation in Ukrainian Math. J. 45 (1993), no. 6, 890--917 (1994)
    MR 96a:30042
  49. Stepanets, A. I.; Kulik, A. N.
    Approximation of functions in the class by de la Vallee-Poussin sums. (Russian) Mat. Fiz. Nelinein. Mekh. No. 17(51), (1992), 20--27.
    MR 94k:42011
  50. Stepanets, A. I.
    Approximation of functions defined by Cauchy-type integrals. (Russian) Fourier series: theory and applications (Russian), 127--141, Akad. Nauk Ukrainy, Inst. Mat., Kiev, 1992.
    MR 94k:30098
  51. Stepanets, A. I.
    Some remarks on approximation of functions of high smoothness by Fourier operators. (Russian) Ukrain. Mat. Zh. 44 (1992), no. 1, 138--141; translation in Ukrainian Math. J. 44 (1992), no. 1, 126--129
    MR 94h:42017
  52. Stepanets, A. I.
    Approximations in spaces of locally integrable functions. (Russian) Akad. Nauk Ukrainy Inst. Mat. Preprint 1993, no. 18, 47 pp.
    MR 94g:41040
  53. Stepanets, A. I.; Romanyuk, V. S.
    Classes of -differentiable functions of a complex variable and approximation by linear means of their Faber series. (Russian) Ukrain. Mat. Zh. 44 (1992), no. 11, 1556--1570; translation in Ukrainian Math. J. 44 (1992), no. 11, 1432--1446 (1993)
    MR 93m:41022
  54. Stepanets, A. I.; Romanyuk, V. S.
    Classes of -differentiable functions of a complex variable and their approximation by linear means of Faber series. (Russian) Akad. Nauk Ukrainy Inst. Mat. Preprint 1992, no. 15, i, 1--28.
    MR 93k:30066
  55. Stepanets, A. I.; Pachulia, N. L.
    Multiple Fourier sums on sets of -differentiable functions. (Russian) Ukrain. Mat. Zh. 43 (1991), no. 4, 545--555; translation in Ukrainian Math. J. 43 (1991), no. 4, 504--512
    MR 93j:42013
  56. Stepanets, A. I.
    An approximation of Cauchy-type integrals. (Russian) Akad. Nauk Ukrainy Inst. Mat. Preprint 1992, no. 1, 42 pp.
    MR 93j:30043
  57. Stepanets, A. I.
    A new classification of periodic functions and their approximation. Translated from the Russian by Jerzy Trzeciak. Banach Center Publ., 22, Approximation and function spaces (Warsaw, 1986), 437--447, PWN, Warsaw, 1989.
    MR 93e:42008
  58. Gavrilyuk, V. T.; Stepanets, A. I.
    Problems of saturation of linear methods. (Russian) Ukrain. Mat. Zh. 43 (1991), no. 3, 291--308; translation in Ukrainian Math. J. 43 (1991), no. 3, 255--272
    MR 93b:42005
  59. Stepanets, A. I.; Stepanets, N. I.
    Approximation by entire functions in the mean on the real axis. (Russian) Ukrain. Mat. Zh. 43 (1991), no. 1, 121--125; translation in Ukrainian Math. J. 43 (1991), no. 1, 100--104
    MR 92m:41053
  60. Stepanets, A. I.; Pachulia, N. L.
    Multiple Fourier sums on sets of -differentiable functions. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1990, no. 55, 1--16.
    MR 92h:42025
  61. Stepanets, A. I.
    Classes of functions defined on the real axis, and their approximations by entire functions. II. (Russian) Ukrain. Mat. Zh. 42 (1990), no. 2, 210--222; translation in Ukrainian Math. J. 42 (1990), no. 2, 186--197
    MR 92e:41015
  62. Stepanets, A. I.
    Classes of functions defined on the real axis, and their approximations by entire functions. I. (Russian) Ukrain. Mat. Zh. 42 (1990), no. 1, 102--112; translation in Ukrainian Math. J. 42 (1990), no. 1, 93--102
    MR 92e:41014
  63. Stepanets, A. I.; Zaderei, P. V.; Zaderei, N. N.
    Fourier coefficients of functions of the class . (Russian) Ukrain. Mat. Zh. 42 (1990), no. 11, 1537--1545; translation in Ukrainian Math. J. 42 (1990), no. 11, 1380--1387 (1991)
    MR 92c:42010
  64. Stepanets, A. I.; Pachulia, N. L.
    Strong mean deviations of Fourier operators. (Russian) Ukrain. Mat. Zh. 42 (1990), no. 9, 1225--1231; translation in Ukrainian Math. J. 42 (1990), no. 9, 1090--1095 (1991)
    MR 92b:42012
  65. Stepanets, A. I.; Drozd, V. V.
    Simultaneous approximation of functions and their derivatives by Fourier operators in the uniform metric. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1989, no. 17, 3--19.
    MR 91k:41036
  66. Bushev, D. N.; Stepanets, A. I.
    Approximation of weakly differentiable periodic functions. (Russian) Ukrain. Mat. Zh. 42 (1990), no. 3, 406--412; translation in Ukrainian Math. J. 42 (1990), no. 3, 361--366
    MR 91c:42001
  67. Stepanets, A. I.
    Simultaneous approximation of functions and their -derivatives by Fourier sums. (Russian) Ukrain. Mat. Zh. 41 (1989), no. 2, 211--222, 287; translation in Ukrainian Math. J. 41 (1989), no. 2, 189--199
    MR 90k:42011
  68. Stepanets, A. I.; Zhukina, E. I.
    Inverse theorems for the approximation of -differentiable functions. (Russian) Ukrain. Mat. Zh. 41 (1989), no. 8, 1106--1112, 1151; translation in Ukrainian Math. J. 41 (1989), no. 8, 953--958 (1990)
    MR 90k:42007
  69. Pachulia, N. L.; Stepanets, A. I.
    Strong summability of Fourier series in classes of -differentiable functions. (Russian) Mat. Zametki 44 (1988), no. 4, 506--516, 557.
    MR 90i:42011
  70. Stepanets, A. I.
    Deviations of Fourier sums on classes of entire functions. (Russian) Ukrain. Mat. Zh. 41 (1989), no. 6, 783--789, 862; translation in Ukrainian Math. J. 41 (1989), no. 6, 672--677 (1990)
    MR 90i:42009
  71. Stepanets, A. I.
    On the Lebesgue inequality on classes of -differentiable functions. (Russian) Ukrain. Mat. Zh. 41 (1989), no. 4, 499--510, 575; translation in Ukrainian Math. J. 41 (1989), no. 4, 435--443
    MR 90h:42003
  72. Stepanets, A. I.
    V. K. Dzyadyk's research on the theory of approximating periodic functions. (Russian) Ukrain. Mat. Zh. 41 (1989), no. 4, 436--441, 574; translation in Ukrainian Math. J. 41 (1989), no. 4, 379--383
    MR 90f:01054a
  73. Stepanets, A. I.; Pachulia, N. L.
    Estimates for strong mean deviations of Fourier operators in the uniform metric. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1988, no. 27, 48--56.
    MR 90e:42009c
  74. Stepanets, A. I.; Stepanets, N. I.
    Approximation by entire functions in the mean. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1988, no. 27, 42--47.
    MR 90e:42009b
  75. Stepanets, A. I.
    Approximation by entire functions in the uniform metric. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1988, no. 27, 3--41.
    MR 90e:42009a
  76. Stepanets, A. I.
    Fourier sums: new results and unsolved problems. (Russian) Ukrain. Mat. Zh. 40 (1988), no. 5, 547--562, 676; translation in Ukrainian Math. J. 40 (1988), no. 5, 467--481 (1989)
    MR 90c:42008
  77. Stepanets, A. I.
    Classification and approximation of periodic functions. (Russian) ``Naukova Dumka'', Kiev, 1987. 268 pp.
    MR 90b:42007
  78. Stepanets, A. I.
    Approximation by Fourier operators of functions that are defined on the real axis. (Russian) Dokl. Akad. Nauk SSSR 303 (1988), no. 1, 50--53; translation in Soviet Math. Dokl. 38 (1989), no. 3, 492--495
    MR 90b:41037
  79. Stepanets, A. I.; Pachulia, N. L.
    Rate of convergence of a group of deviations in the space . (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1987, no. 40, 3--8.
    MR 89i:42010
  80. Stepanets, A. I.
    The mean-square rate of convergence of orthogonal series. (Russian) Ukrain. Mat. Zh. 39 (1987), no. 5, 606--611, 679.
    MR 89f:42004
  81. Stepanets, A. I.
    Approximation by Fourier operators of functions given on the real axis. (Russian) Ukrain. Mat. Zh. 40 (1988), no. 2, 198--209, 271; translation in Ukrainian Math. J. 40 (1988), no. 2, 169--179
    MR 89d:42008
  82. Stepanets, A. I.; Pachulia, N. L.
    On the behavior of a group of deviations on sets of -differentiable functions. (Russian) Ukrain. Mat. Zh. 40 (1988), no. 1, 101--105, 135; translation in Ukrainian Math. J. 40 (1988), no. 1, 85--89
    MR 89b:42008
  83. Stepanets, A. I.; Kushpel', A. K.
    Rate of convergence of Fourier series and best approximations in the space Lp. (Russian) Ukrain. Mat. Zh. 39 (1987), no. 4, 483--492, 543.
    MR 89a:42008
  84. Stepanets, A. I.
    Best approximations for infinitely differentiable functions in the spaces Ls. (Russian) Mat. Zametki 42 (1987), no. 1, 21--32, 166.
    MR 88m:41020
  85. Stepanets, A. I.
    Approximations on classes of -differentiable functions. (Russian) Dokl. Akad. Nauk SSSR 293 (1987), no. 4, 797--800.
    MR 88i:42012
  86. Stepanets, A. I.
    Approximation by Fourier sums of functions with slowly decreasing Fourier coefficients. (Russian) Ukrain. Mat. Zh. 38 (1986), no. 6, 755--762, 815.
    MR 88h:42006
  87. Stepanets, A. I.; Stepanets, N. I.
    The rate of convergence of Fourier series in the metric L. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1986, no. 66, 53--56.
    MR 88f:42013c
  88. Stepanets, A. I.; Pachulia, N. L.
    On the strong summability of Fourier series in the spaces . (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1986, no. 66, 48--52.
    MR 88f:42013b
  89. Stepanets, A. I.
    The rate of convergence of Fourier series in the spaces . (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1986, no. 66, 3--48.
    MR 88f:42013a
  90. Stepanets, A. I.; Zhukina, E. I.
    Imbedding conditions for certain classes. (Russian) Some problems in the theory of approximation of functions (Russian), 121--125, 148, Akad. Nauk Ukrain. SSR, Kiev, 1985.
    MR 88d:42008
  91. Stepanets, A. I.
    Moduli of half-decay of monotone functions and the rate of convergence of Fourier series. (Russian) Ukrain. Mat. Zh. 38 (1986), no. 5, 618--624, 679.
    MR 88c:42011
  92. Stepanets, A. I.
    Classification of periodic functions and the rate of convergence of their Fourier series. (Russian) Izv. Akad. Nauk SSSR Ser. Mat. 50 (1986), no. 1, 101--136, 208.
    MR 88a:42003
  93. Stepanets, A. I.
    Approximation of infinitely differentiable periodic functions. (Russian) Reports of the extended sessions of a seminar of the I. N. Vekua Institute of Applied Mathematics, Vol. I, no. 2 (Russian) (Tbilisi, 1985), 133--135, 187, Tbilis. Gos. Univ., Tbilisi, 1985.
    MR 87j:42013
  94. Stepanets, A. I.; Novikova, A. K.
    Approximation of periodic functions by Fourier sums in the mean. (Russian) Ukrain. Mat. Zh. 38 (1986), no. 2, 204--210, 269.
    MR 87h:42007
  95. Stepanets, A. I.
    On the problem of simultaneous approximation of functions and their -derivatives. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1985, no. 7, 3--21.
    MR 87f:42005
  96. Stepanets, A. I.; Pachulia, N. L.
    Strong summability of Fourier series. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1985, no. 61, 3--13.
    MR 87e:42012a
  97. Stepanets, A. I.
    The order relation for -derivatives. (Russian) Ukrain. Mat. Zh. 37 (1985), no. 5, 645--648, 679.
    MR 87d:42012
  98. Sorich, N. N.; Stepanets, A. I.
    Simultaneous approximation of periodic functions and their derivatives. (Russian) Mat. Zametki 36 (1984), no. 6, 873--882, 942.
    MR 86j:42002
  99. Stepanets, A. I.
    Approximation by Fourier sums of functions with slowly decreasing Fourier coefficients. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1984, no.43, 3--25.
    MR 86h:42005
  100. Stepanets, A. I.
    Deviations of Fourier sums on classes of infinitely differentiable functions. (Russian) Ukrain. Mat. Zh. 36 (1984), no.6, 750--758.
    MR 86e:42010
  101. Stepanets, A. I.
    Classes of periodic functions and the approximation of their elements by Fourier sums. (Russian) Dokl. Akad. Nauk SSSR 277 (1984), no. 5, 1074--1077.
    MR 85k:42009
  102. Stepanets, A. I.; Kushpel', A. K.
    Best approximations and diameters of classes of periodic functions. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1984, no. 15, 44 pp.
    MR 85j:42004
  103. Stepanets, A. I.
    The behavior of sequences of partial Fourier sums of continuous functions near their points of divergence. (Russian) Ukrain. Mat. Zh. 35 (1983), no.5, 652--653.
    MR 85d:42006
  104. Stepanets, A. I.
    Sharp estimates of multiple integrals on classes of continuous functions of several variables and their application. (Russian) Constructive function theory '81 (Varna, 1981), 157--161, Bulgar. Acad. Sci., Sofia, 1983.
    MR 85b:42007
  105. Stepanets, A. I.
    Classification of periodic functions and approximation by their Fourier sums. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1983, no. 69, 57 pp.
    MR 85b:42002
  106. Stepanets, A. I.
    Simultaneous approximation of a pair of conjugate functions. Mat. Zametki 34 (1983), no. 5, 641--650.
    MR 85a:42005
  107. Stepanets, A. I.
    Upper bounds for Fourier coefficients on classes of continuous functions of several variables. (Russian) Izv. Akad. Nauk SSSR Ser. Mat. 46 (1982), no. 3, 650--665, 672.
    MR 84j:42023
  108. Stepanets, A. I.
    Classes of periodic functions and approximation of their elements by Fourier sums. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1983, no. 10, 57 pp.
    MR 84j:42006
  109. Stepanets, A. I.
    Asymptotic representations of deviations of Zygmund means from differentiable periodic functions. (Russian) Methods of approximation theory and their applications, 96--115, Akad. Nauk Ukrain. SSR, Inst. Mat., Kiev, 1982.
    MR 84i:42005
  110. Stepanets, A. I.; Rukasov, V. I.
    Approximation by Fourier sums of triangular type on classes of continuous periodic functions of two variables. (Russian) Ukrain. Mat. Zh. 35 (1983), no. 2, 249--254.
    MR 84h:42004
  111. Stepanets, A. I.
    Simultaneous approximation of conjugate functions and their derivatives by Fourier sums. (Russian) Investigations in the theory of approximation of functions, pp. 82--88, 103, Akad. Nauk Ukrain. SSR, Inst. Mat., Kiev, 1981.
    MR 84e:42018
  112. Stepanets, A. I.
    Uniform approximation by trigonometric polynomials (Russian) Linear methods ``Naukova Dumka'', Kiev, 1981. 340 pp.
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    Approximation of periodic functions of several variables by de la Vallee-Poussin sums. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1981, no. 10, 3--16.
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    Simultaneous approximation of periodic functions and their derivatives by Fourier sums. (Russian) Questions of the theory of the approximation of functions (Russian), pp. 159--165, 201, Akad. Nauk Ukrain. SSR, Inst. Mat., Kiev, 1980.
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    Exact estimates of Fourier coefficients of classes of continuous and differentiable periodic functions of several variables. (Russian) Dokl. Akad. Nauk SSSR 261 (1981), no. 1, 34--38.
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    On simultaneous approximation of periodic functions and their derivatives by Fourier sums. (Russian) Ukrain. Mat. Zh. 33 (1981), no. 3, 356--367.
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    Asymptotic formulas for the roots of the cosine integral. (Russian) Questions of the theory of the approximation of functions (Russian), pp. 154--159, 200, Akad. Nauk Ukrain. SSR, Inst. Mat., Kiev, 1980.
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    Asymptotically exact estimates of the deviations of partial Fourier sums on classes of continuous periodic functions of several variables. (Russian) Ukrain. Mat. Zh. 33 (1981), no. 1, 119--123.
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    Simultaneous approximation of periodic functions and their derivatives by Fourier sums. (Russian) Dokl. Akad. Nauk SSSR 254 (1980), no. 3, 543--544.
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    Estimates of deviations of partial Fourier sums on classes of continuous periodic functions of several variables. (Russian) Izv. Akad. Nauk SSSR Ser. Mat. 44 (1980), no. 5, 1150--1190, 1214.
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    On the approximation of conjugate functions from Holder classes by Fejer means. Anal. Math. 5 (1979), no. 2, 167--178.
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    Approximation by Fourier sums on classes of periodic functions defined by polyharmonic operators. (Russian) Mat. Zametki 27 (1980), no. 4, 569--581, 669.
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    Exact estimates of deviations of Favard sums on classes of continuous periodic functions of two variables. (Russian) Ukrain. Mat. Zh. 32 (1980), no. 4, 528--537.
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    The solution in rearrangements of an extremal problem for classes of continuous functions of two variables in permutations. (Russian) Ukrain. Mat. Zh. 31 (1979), no. 1, 95--101, 112.
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    Elements of the behavior of the Favard kernel. (Russian) The theory of functions and its applications (Russian), pp. 154--193, 212, "Naukova Dumka", Kiev, 1979.
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    A sharp estimate of the deviations of Favard sums over the classes H1,A,1B. (Russian) Studies in the theory of approximation of functions and their applications (Russian), pp. 174--181, 195, Akad. Nauk Ukrain. SSR, Inst. Mat., Kiev, 1978.
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    Approximation by Fourier sums of continuous functions of two variables. (Russian) The theory of the approximation of functions (Proc. Internat. Conf., Kaluga, 1975) (Russian), pp. 330--332, "Nauka", Moscow, 1977.
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    Approximation of convolution classes by Fourier sums. (Russian) Fourier series: theory and applications (Ukrainian) (Kamenets-Podolskiy, 1997), 323--337, Pr. Inst. Mat. Nats. Akad. Nauk Ukr. Mat. Zastos., 20, Natsional. Akad. Nauk Ukraini, Inst. Mat., Kiev, 1998.
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    Simultaneous approximation of periodic functions of two variables and their -derivatives by Fourier sums. (Russian) Investigations in the theory of the approximation of functions (Russian), 106--117, 124, Akad. Nauk Ukrain. SSR, Inst. Mat., Kiev, 1987.
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    Approximation of periodic functions by Fourier sums in an integral metric. (Russian) Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1984, no. 43, 26--54.
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    Distribution of zeros of special functions generated by trigonometric integrals. (Russian) Approximation of continuous periodic functions by linear methods. Akad. Nauk Ukrain. SSR Inst. Mat. Preprint 1982, no. 48, 3--34.