The Scientific Journal
FACTA UNIVERSITATIS
Series Mathematics and Informatics
ISSN 0352 – 9665



Editor-in-Chief
Predrag S. Stanimirović
University of Niš
Faculty of Science and Mathematics
Department of Computer Science
P.O. Box 224, Višegradska 33, 18000 Niš, Serbia
Phone: +381 18 224 492
Fax: +381 18 533 014
e-mail: pecko@pmf.ni.ac.rs

Associate editor
Jelena Manojlović
Faculty of Science and Mathematics
Department of Mathematics,
e-mail: jelenam@pmf.ni.ac.rs,

Founding Editor
Gradimir V. Milovanović
Serbian Academy of Sciences and Arts, and
Megatrend University, Faculty of Computer Sciences,
Belgrade, Serbia
e-mail: gvm@megatrend.edu.rs, gvm@sbb.rs

 AREA EDITORS:

Aleksandar Cvetković*
      Approximation Theory, Numerical Analysis
Dragana Cvetković Ilić*
      Linear Algebra, Operator Theory
Jelena Ignjatović*
      Algebra, Fuzzy Mathematics, Theoretical Computer Science
Ljubiša Kocić**
     Fractal Geometry, Chaos Theory, Computer Aided Geometric Design
Jelena Manojlović*
      Differential Equations
Gradimir Milovanović
      Approximation Theory, Numerical Analysis
Emina Milovanović**
     Parallel Computing, Computer Architecture
Dijana Mosić*
      Mathematical and Functional Analysis
Miroslav Ristić*
      Statistics, Time Series Analysis
Predrag Stanimirović*
      Symbolic and Algebraic Computation, Operations Research
Milena Stanković**
      Internet Technologies, Software Engineering
Dragan Stevanović*
      Discrete Mathematics, Graph and Combinatorial Algorithms


 EDITORIAL BOARD:

R. P. Agarwal, Melbourne, FL, USA
O. Agratini, Cluj-Napoca, Romania
S. Bogdanović, Niš, Serbia
M. Ćirić, Niš, Serbia
D. Cvetković, Belgrade, Serbia
D. K. Dimitrov, Sao Jose do Rio Preto, Brazil
S. S. Dragomir, Victoria, Australia
D. S. Djordjevic, Niš, Serbia
M. Droste, Leipzig, Germany
A. Guessab, Pau, France
A. Ivić, Belgrade, Serbia
S. V. Janković, Niš, Serbia
B. S. Kašin, Moscow, Russia
Lj. Kočinac, Niš, Serbia
G. Mastroianni, Potenza, Italy
P. S. Milojević, Newark, NJ, USA
I. Ž. Milovanović, Niš, Serbia
Lj. Petković, Niš, Serbia
S. Pilipović, Novi Sad, Serbia
V. Rakočević, Niš, Serbia
Th. M. Rasssias, Athens, Greece
S. Saitoh, Kiryu, Japan
H. M. Srivastava, Victoria, Canada
R. Stanković, Niš, Serbia
A. Tepavčević, Novi Sad, Serbia
H. Vogler, Dresden, Germany

* University of Niš, Faculty of Science and Mathematics, Department of Mathematics and Informatics, P.O. Box 224, Višegradska 33, 18000 Niš, Serbia
** University of Niš, Faculty of Electronic Engineering, P.O. Box 73, 18000 Niš, Serbia
Technical Editor: Aleksandar Ilić, Faculty of Science and Mathematics, Department of Mathematics and Informatics, P.O. Box 224, Višegradska 33, 18000 Niš, Serbia