PROF.DR. CİHAN ORHAN    
Name : CİHAN
Surname : ORHAN
E-Mail : orhan@science.ankara.edu.tr
Phone Number : (0312)212 6720 / 1248
Title : PROF.DR.
Unit : FACULTY OF SCIENCES
Department : DEPARTMENT OF MATHEMATICS
Personal Information

 

                                               CURRICULUM VITAE

Prof.Dr.Cihan Orhan 

Ankara University, Faculty of Science,

Department of Mathematics,

Tandoğan 06100,Ankara, TURKEY.

    EDUCATION

PhD :            1981           Ankara University, 

MSc :             1978            Ankara  University,

BSc:              1976          Ankara University,

Academic   Positions : 

Professor:           1993 - …               Ankara University,

Assoc. Prof.   :     1987 – 1993        Ankara University,

Assit. Prof.           1984 – 1987       Ankara University,

Reseach Assist.  1981 – 1984      Ankara University, 


 ADMINISTRATIVE DUTIES: Chairman of the Department of Mathematics ( 2008-2017). 

 

 Interest of Research

Analysis, Functional Analysis, Sequence Spaces and Summability, Korovkin type approximation theory 

 Visiting Positions

May 1985 – May 1986    Birmingham University , England.

15 Sept – 30 Nov 1990    Kent State University, OH, USA.   

16 Aug – 14 Nov 2003    Kent State University, OH, USA.   

18 Aug- 1 Sept 2004       FernUniversität in Hagen, Germany.

 


 

                             PUBLICATIONS

[67] M.Ünver and C.Orhan, Statistical Convergence with respect to Power Series Methods and Applications to Approximation Theory, Numerical Functonal Analysis and Applications, to appear, (SCI-Exp)

[66] N.Ş.Bayram and C.Orhan, Abel Convergence of the Sequence of Positive Linear Opeators in  Lp,q(loc), Bull.Belgian Math Soc.-Simon Stevin,to appear, ( SCI-Exp)

[65] E.Taş and C.Orhan, Characterization of q-Cesaro convergence for double sequences, Stud. Univ. Babeş-Bolyai Math. 62(2017), No. 3, 367-376.

[64] T.Yurdakadim and C.Orhan, Some Inequalities and Functionals related to Generalized Limits, Math.Reports, 19(69), 2 (2017), 145-155.  (SCI-Expanded).


[63] T.Yurdakadim, M.K.Khan, H.I.Miller and C.Orhan, Generalized Limits and Statistical Convergence, Mediterr. J. Math. 13 (2016), no.3, 1135-1149.  (SCI-Expanded)

[62] A.Leonov and C.Orhan, On Filter Convergence of Series, Real Anal.Exchange, 40(2014-2015), no.2, 459-473.

 [61] M.Ünver and C.Orhan; Matrix characterization of A-statistical convergence of double sequences,  Acta Math.Hungarica,143(2014), no.1,159-175. (SCI-Expanded)

 [60] M.Ünver, M.K.Khan and C.Orhan; A-Distributional summability in topological spaces, Positivity ,18 (2014), no.1, 131-145. (SCI-Expanded).

 [59] C.Orhan and İ.Sakaoglu; Rate of convergence in Lp approximation, Periodica Math.Hungarica ,68(2014),no2,176-184 (SCI-Expanded)

 [58]  C.Orhan and İ.Sakaoglu;  Strong summation process in Lp spaces, Nonlinear Analysis, 85 (2013), 89-94. (SCI)

 [57]  C.Orhan, E.Taş, T.Yurdakadim; The Buck-Pollard Property for p-Cesaro Matrices, Numerical Functional Analysis and Optinization, 33(2012),190-196. (SCI-Expanded)

 [56] V. Kadets, A. Leonov and C. Orhan; Weak statistical convergence and weak filter convergence for  unbounded sequences, J. Math. Anal. Appl. 371(2010), 414-424 . (SCI)

 [55] M.K.Khan and C.Orhan, Characterizations of Strong and Statistical Convergences, Publ. Math. Debrecen,  76(2010),77-88. (SCI-Expanded)

 [54] Ö.G.Atllıhan, H.G.İnce and C.Orhan; Some Variations of the Bohman-Korovkin Theorem,  Mathematical and Computer Modelling, 50(2009),1205-1210. (SCI).

 [53]  Ö.G.Atllıhan and C.Orhan; Summation process of positive linear operators,  Computers and mathematics with Applications 56( 2008), 1188-1195. (SCI).

 [52]  O.Duman and C.Orhan, Rates of A-Statistical Convergence of operators in the space of locally integrable functions; Appl. Math.Letters 21(2007), 431-435. (SCI).

 [51]   M.K.Khan and C.Orhan, Matrix characterization of  A-statistical convergence; J. Math. Anal. Appl. 335(2007), 406-417.  (SCI )                                                                                    

[50]  Ö.G.Atlihan and C.Orhan, Matrix summability and positive linear operators, Positivity  11(2007),  387-398. (SCI-Expanded)

 [49] J. Connor , J. A. Fridy and C. Orhan, Core equality results for sequences; J. Math. Anal. Appl. 321 (2006), 515-523.   (SCI)

 [48] C. Orhan, Some inequalities between functionals on bounded sequences; Studia  Sci. Math. Hungarica,  44(2007), 225-232.  (SCI-Expanded)

 [47] O. Duman and C. Orhan, An abstract version of the Korovkin approximation theorem; Publ. Math. Debrecen:  69 (2006), 33-46.   (SCI-Expanded)

 [46] O. Duman and C. Orhan, Rates of A-Statistical convergence of positive linear operators; Appl. Math. Letters, 18 (2005), 1339-1344. (SCI)

 [45] F.Móricz and C.Orhan, Tauberian conditions under which statistical convergence follows from statistical summability by weighted means, Studia Sci.Math.Hungarica, 41 (2004), 391- 403.  (SCI-Expanded)

 [44] O.Duman and C.Orhan, Statistical approximation by positive linear operators, Studia Math. 161 (2004), 187-197.   (SCI)

    [43] O.Duman, M.K.Khan and C.Orhan,  A-statistical convergence of approximating operators,  Math.Inequalities &Appl. 6 (2003), 689-699. (SCI)

 [42] H.I.Miller and C.Orhan, Statistical (T) rates of  convergence,  Glasnik  Matematicki, 39 (2004), 101-110.

 [41] K.Demirci, M.K.Khan and C.Orhan, Subspaces of A-statistically convergent sequences,  Studia Sci.Math.Hungarica, 40 (2003), 183-190. (SCI-Expanded)

 [40] O.Doğru, O.Duman and C.Orhan, Statistical approximation  by generalized Meyer-König and Zeller type operators, Studia Sci.Math.Hungarica,40(2003),359-371. (SCI-Expanded)

 [39] O.Duman and C.Orhan, Statistical approximation in the space of locally integrable functions, Publ.Math.Debrecen , 63  (2003), 133-144. (SCI-Expanded)

 [38] K.Demirci,M.K.Khan and C.Orhan, Strong and A-statistical comparisions for sequences, J.Math.Anal.Appl. 278 (2003), 27-33. (SCI)

    [37] O.Duman and C.Orhan, mu-Statistically convergent function sequences, Czechoslovak Math.J. 54 (2004), 413-422. (SCI-Expanded)

 [36] J.Connor, K.Demirci and C.Orhan, Multipliers and factorizations for bounded statistically convergent sequences, Analysis, 22(2002),321-333.

 [35] J.A.Fridy, H.I.Miller and C.Orhan, Statistical rates of convergence, Acta Sci.Math.( Szeged), 69 (2003), 147-157.

 [34] C.Orhan and S.Yardimci, Banach and statistical cores of bounded sequences, Czechoslovak Math.J. 54 (2004), 65-72. (SCI-Expanded)

 [33] A.D.Gadjiev and  C.Orhan, Some approximation theorems via statistical convergence, Rocky Mountain J.Math. 32(2002), 129-138.  (SCI-Expanded)

 [32] H.I.Miller and C.Orhan, On almost convergent  and statistically convergent subsequences. Acta Math.Hungarica, 93(2001),135-151. (SCI-Expanded)

 [31] Demirci, K.; Orhan, C. Bounded multipliers of bounded A-statistically convergent sequences. J. Math. Anal. Appl. 235 (1999), no. 1, 122--129. (SCI)

 [30] C. Orhan,  Translativity of absolute weighted mean summability. Czechoslovak Math. J. 48(123) (1998), 755-761. (SCI-Expanded)

 [29] C. Orhan and Ö. Çakar, Some inclusion theorems for absolute summability. Czechoslovak Math. J. 46(121) (1996), no. 4, 599--605. (SCI-Expanded)

 [28] J. A. Fridy and C. Orhan, Statistical core theorems. J. Math. Anal. Appl. 208 (1997), no. 2, 520--527.  (SCI)

  [27] J. A. Fridy and C. Orhan, Statistical limit superior and limit inferior. Proc. Amer. Math. Soc. 125 (1997), no. 12, 3625--3631. (SCI)

  [26] C. Orhan, FK spaces that include strongly A-summable sequences. Demonstratio Math. 29 (1996), no. 2, 371--375.

  [25] C. Orhan and M. A. Sarigöl, Absolute summability of infinite series. Proc. Indian Acad. Sci. Math. Sci. 105 (1995), no. 2, 201—205. (SCI-Expanded)

  [24] C. Orhan, A short note on weighted mean summability. Indian J. Pure Appl. Math. 26 (1995), no. 1, 63--67.  (SCI-Expanded)

  [23] J. A. Fridy and C. Orhan, Lacunary statistical summability. J. Math. Anal. Appl. 173 (1993), no. 2, 497--504.  (SCI)

  [22] C. Orhan, Conull absolute summability domains. Indian J. Pure Appl. Math. 24 (1993), no. 9, 539--542. (SCI-Expanded)

  [21] C. Orhan and M. A. Sarigöl, On absolute weighted mean summability. Rocky Mountain J. Math. 23 (1993), no. 3, 1091--1098.  (SCI-Expanded)

  [20] J. A. Fridy and C. Orhan, Lacunary statistical convergence. Pacific J. Math. 160 (1993), no. 1, 43--51.  (SCI)

  [19] C. Orhan and Ö. Çakar, Almost A-boundedness and absolute almost summability. Bull. Calcutta Math. Soc. 83 (1991), no. 6, 527--530.

  [18] C. Orhan, Some inequalities involving sublinear functionals. Comment. Math. Prace Mat. 31 (1991), 89--96.

  [17] C. Orhan, On F-absolutely equivalent summability methods. Bull. Calcutta Math. Soc. 82 (1990), no. 4, 303--306.

  [16] E. Savas and C. Orhan, On strongly sigma-regular summability methods. Bull. Calcutta Math. Soc. 83 (1991), no. 1, 51--54.

  [15] Ö. Çakar and C. Orhan, A note on absolute summability. Bull. Calcutta Math. Soc. 83 (1991), no. 1, 29--34.

  [14] C. Orhan, Sublinear functionals and Knopp's core theorem. Internat. J. Math. Math. Sci. 13 (1990), no. 3, 461--468.

  [13] C. Orhan, On equivalence of summability methods. Math. Slovaca 40 (1990), no. 2, 171--176.

  [12] C. Orhan, Almost A-boundedness. J. Inst. Math. Comput. Sci. Math. Ser. 1 (1988), no. 2, 121--125.

   [11] M. S. Macphail and C. Orhan, Some properties of absolute summability domains. Analysis 9 (1989), no. 4, 317--322.

   [10] C. Orhan and M. A. Sarıgöl, On F-absolutely translative summability methods. Indian J. Pure Appl. Math. 20 (1989), no. 9, 893--898.  (SCI-Expanded)

  [9] C. Orhan, On absolute summability. Bull. Inst. Math. Acad. Sinica 15 (1987), no. 4, 433--437.

    [8] C. Orhan, Absolutely p-th power conservative matrices. Comm. Fac. Sci. Univ. Ankara Ser. A- 1 Math. Statist. 35 (1986), no. 1-2, 61--65.

 [7] C. Orhan, F-absolute equivalence of F-regular summability methods. Comm. Fac. Sci. Univ.Ankara Sér. A-1 Math. 33 (1984), no. 23, 188--192.

    [6] C. Orhan, Strongly almost regular dual summability methods. Pure Appl. Math. Sci. 24 (1986), no. 1-2, 9--13.

    [5] C. Orhan and E. Öztürk, E. On F-regular dual summability methods. Bull. Inst. Math. Acad. Sinica 14 (1986), no. 1, 99--104.

    [4] C. Orhan, On the summability field of l-l methods of summation. Comm. Fac. Sci. Univ. Ankara Sér. A- 1 Math. 31 (1982), no. 9, 79--88 (1983).

    [3] C. Orhan, Almost regularity of dual summability methods. Comm. Fac. Sci. Univ. Ankara Sér. A- 1 Math. 33 (1984), no. 2, 9--13.

    [2] C. Orhan, Matrix transformations on Cesàro difference sequence spaces. Comm. Fac. Sci. Univ. Ankara Sér. A-1 Math. 33 (1984), no. 1, 1--8.

    [1] C. Orhan, Cesàro difference sequence spaces and related matrix transformations. Comm. Fac. Sci. Univ. Ankara Sér. A-1 Math. 32 (1983), no. 8, 55--63 (1984),.

 

           International Conferences

 

  1. International Workshop on Sequence Spaces & Applications:Ankara University,

            Ankara / Turkey, 10-16 August 1998.

           " Statistical core theorems".  

               

  1. Bosnian-Croatian Analysis Meeting: Bihac/ Bosnia & Herzegovina, 10-12 May 2001.

      " Multipliers and factorizations for bounded statistically    

       convergent sequences".

 

  1. Fourth European Congress of Mathematics: Stockholm / Sweeden, 27 June- 2 July 2004.

Poster: Rates of A-Statistical convergence of positive linear operators.

 

      4.  Fejer-Riesz Conference: Eger / Hungary, 8-14 June 2005.

           " Matrix characterization of A-Statistical convergence".

     

  1. International Conference on Numerical Analysis and Approximation Theory:

Cluj-Napoca / Romania, 5-8 July 2006.

"Matrix summability and positive linear operators".

 

6.   Second Bosnian Mathematical Conference , University of Sarajevo,

Sarajevo / Bosnia & Herzegovina , 23-24 June 2007.

" Summation Process of Positive Linear Operators".

 

      7.   17th Summer St.Petersburg Meeting in Analysis,  June 23-28 , 2008,

 St.Petersburg, Russia.

 

      8.   6th  International Conference on Functional Analysis and Approximation Theory,

            September 24-30, 2009. Acquafredda di Maratea / Italy.

           " Some Variations of the Bohman-Korovkin Theorem". 

       9. International Conference on Summablity and Applications, May 12-13, 2012.

            Istanbul Commerce University, Istanbul.

 

     10. International Conference on Applied Mathematics and Approximation Theory,

            May 17-20, 2012 . TOBB University of Economics and Technology,  Ankara.

            "Weak Fitler Convergence for unbounded Sequences".       

    11. 2 nd International Eurasian Conference on  Mathematical Sciences and Applications,  (IECMSA)  August  26-29 , 2013.  International University of Sarajevo, Bosnia and Herzegovina.

 " Buck Pollard Property for (C,1,1) Method."

   12. 3rd International Eurasian Conference on Mathematical Sciences and Applications (IECMSA).  August 25—28, 2014. Technical University of Vienna, Vienna, Austria.

 " Generalized Limits and Statistical Covergence ".

   13.International Conference on Numerical Analysis and Approximation Theory,  September 6-9,  2018. Cluj-Napoca, Romania.

  " The Scottish Cafe and Statistical Convergence."

  

  

 

 

                            SUPERVISED GRADUATE STUDENTS (PHD)

  1. Cafer Coşkun; “Spectrums of  Weigthed means  and p-Cesaro operators" ,

      Ankara University, 1992.

  1. Şeyhmus Yardımcı; “Core theorems of real bounded sequences”,

        Ankara University, 1993.

  1. Kamil Demirci; “A-Statistical convergence and multipliers spaces",

      Ankara University, 1998.

  1. İlhan Dağadur; “Cλ-Conull and  Cλ-Wedge Kama FK- Spaces ”,

      Ankara University, 2001.

  1. Oktay Duman; “Statistically convergent function sequences”,

      Ankara University, 2003.

6.  Özlem Girgin Atlıhan, “Positive  Linear operators and Matrix Summability Methods" , Ankara University, 2008.

 7. İlknur Sakaoğlu Özgüç; "Positive Linear Operators and Summation Processes"

    Ankara University, 2013. 

8. Mehmet Ünver, " A Characterization of A-Strong  Convergence of Double Sequences",  Ankara University, 2013.

9. Tuğba Yurdakadim: Generalized Limits and Statistical Convergence, Ankara University, 2015.

10. Emre Taş, Summability Properties of Subsequences of Double Sequeences, Ankara University, 2015.

11. Nilay Şahin Bayram, Lokal İntegrallenbilir Fonksiyon Uzaylarında Toplam Süreçleri, Ankara Üniversitesi, 2017.

 


 

                          SUPERVISED GRADUATE STUDENTS (MSc)

 

  1. Cafer Coşkun; “Spectral Theory and Mercerian theorms via Spectral theory,

       Ankara University, 1989.

  1. Şeyhmus Yardımcı; “Knopp's Core Theorem and its Analogues”, Ankara University, 1989.
  1. Kamil Demirci; “Statistical Convergence”,  Ankara University, 1992.
  2. Ali Akbulut; “H P-Spaces”,  Ankara University, 1998.
  3. İlhan Dağadur; “Conull and  Coregular Summability Fields”, Ankara University, 1995.  
  1. Sevda Karakuş; Statistical Core Theorems for Sequences, Ankara University, 2005.
  1. Filiz Kocabıyık; Statistical Limit Points, Ankara University, 2005.
  2. Fahriye Efedayıoğlu; “Multiplier Spaces of Statistically Convergent Sequences”, Ankara University, 2005.
  1. Tuba Aydoğan; Rates of Convergence and Statistical Convergence, Ankara University, 2006.

10. Özge Şen; Statistical Convergence of Function sequences,   Ankara University, 2007.

11. İlknur Sakaoğlu; Transformations Leaving the Core Invariant of Sequences,  Ankara University, 2007.

12. Çiğdem Çulha; A-Statistical Convergence of of Positive Linear Operators,  Ankara University, 2007.

      13. Mehmet Ünver; Multipliear Spaces of  Summability Fields, Ankara University, 2009.

       14. Tuğba Yurdakadim, Statistically Convergent Subsequences,  Ankara University, 2010.

 15. Emre Taş, Summability of Subsequeences, Ankara University, 2010.

16. Emel Savku, Sequence Spaces with the Hahn Property,  Ankara University, 2010.

17. Rüya Yeğin,  Summability Methods and Iteration, Ankara University, 2011.

 18. Nilay Şahin, Korovkin type Approximations in the Space of Locally Integrable Functions, Ankara University, 2011.

19. Gencay Oğuz, Ergodic Theory and Summability  Methods,

  Ankara University, 2016.

      20. Mustafa Gülfırat, Ideal Convergence and The Bolzano-Weierstrass Property.

       Ankara University, 2018.