International Journal of Pure and Applied Mathematics Editor: Drumi Bainov Medical University of Sofia P.O. Box 45, Sofia 1504, Bulgaria; Fax: 00359-2-987-9874, E-mail: drumibainov@yahoo.com Managing Editor: Svetoslav Nenov Dept. of Mathematics, Univ. of Chemical Technology and Metallurgy 8 Kliment Ohridski Blvd., Sofia 1756, Bulgaria; E-mail: s_nenov@hotmail.com Editorial Board J. Abadie (France) H. Adeli (USA) J. Angelova (Bulgaria) I. Argyros (USA) O. Axelsson (The Netherlands) D. Bainov (Bulgaria) A. Baker (USA) M. Balas (USA) H. Banks (USA) V. Barbu (Romania) P. Bates (USA) G. Beer (USA) J. Bona (USA) G. Buttazzo (Italy) F. Calogero (Italy) J. Cash (UK) C. Castaing (France) E. Cheney (USA) J. Conway (USA) G. Cooperman (USA) G. Da Prato (Italy) C. Dafermos (USA) G. Dantzig (USA) F. Deutsch (USA) E. DiBenedetto (USA) A. Dishliev (Bulgaria) I. Duff (UK) C. Elliott (UK) D. Evans (UK) R. Ewing (USA) R. Finn (USA) T. Fokas (UK) H. Frankowska (France) R. Freund (USA) W. Gautschi (USA) B. Gavish (USA) C. Gear (USA) I. Gladwell (USA) G. Glimm (USA) R. Graham (USA) B. Gramsch (Germany) P. Gresho (USA) C. Groetsch (USA) C. Hess (France) M. Iri (Japan) M. Ito (Japan) J. Jeffers (UK) H. Kawarada (Japan) N. Kenmochi (Japan) D. Kolev (Bulgaria) D. Larson (USA) G. Leitmann (USA) T.-T. Li (P.R. China) P. Lions (France) M. Luskin (USA) V. Milman (Israel) C. Mitchell (UK) B. Mordukhovich (USA) K. Morgan (UK) D. Motreanu (France) Z. Nashed (USA) S. Nenov (Bulgaria) H. Niederreiter (Singapore) G. Nürnberger (Germany) J. Osborn (USA) M. Ôtani (Japan) D. Pallaschke (Germany) C. Pao (USA) N. Pavel (USA) G. Pinder (USA) S. Reich (Israel) M. Renardy (USA) L. Rowen (Israel) P. Sabatier (France) M. Schechter (USA) R. Showalter (USA) C.-W. Shu (USA) M. Shub (USA) P. Souganidis (USA) H.M. Srivastava (Canada) S. Suzuki (Japan) E. Tadmor (USA) A. Tani (Japan) R. Thomas (USA) K. Tomma (USA) R. Varga (USA) W. Vasconcelos (USA) A. Vatsala (USA) N. Velkov (Bulgaria) R. Verma (USA) J. Vines (France) T. Ward (USA) R. Wets (USA) O. Widlund (USA) M. Yasugi (Japan) L. Zadeh (USA) J. Zou (Hong Kong) Aims and Scope The journal will publish carefully selected original research papers from all areas of mathematics. Call for Papers Authors are cordially invited to submit papers in triplicate to the Editor: Drumi Bainov. Manuscripts submitted to this journal will be considered for publication with the understanding that the same work has not been published and is not under consideration for publication elsewhere. Academic Publications INSTRUCTION TO AUTHORS First Author1, Second Author2 1First Author's address, COUNTRY e-mail: authorl@mbox.pharmfac.acad.bg 2Second Author's address, COUNTRY e-mail: author2@math.bas.bg Abstract: The abstract must not exceed 200 words. Leave two lines between the address(es) and abstract. AMS Subj. Classification: 26A33 Key Words: operators for integration and differentiation of fractional order 1. Introduction The manuscript should be prepared only using LaTeX processing system, basic font Roman 12pt size, and must remain legible after small reduction. The papers should be in English and typed in frames 12 * 20 cm (margins 4 cm on left and 5 cm on top) on A4-format white paper. Do not type page numbers. Use pencil to write page numbers on top right comers. On the first page leave 3.5 cm space on the top for the journal's headings, then type the title of the paper in capital letters bold face, leave two lines and type the authors' names and addresses, centered. After the acceptance of the paper for publication, the authors are obliged to submit the LaTeX -source file copied on two 1.44 MB, DOS-formatted, 3.5"-diskettes. 2. Sections, Propositions, Text and Figures Titles of all principal Sections, Acknowledgment, References, Appendices should be typed centered in bold face. Appendices should follow References and be indexed (A, B,...) or enumerated (1,2,...). Paragraphs should have 18pt indent. All subheadings like Definition, Theorem, Lemma, Remark, Example should be indented and in bold face, the text of the propositions (theorems, lemmas, etc.) should be slanted, subheading Proof, also slanted. Reference citations should be typed in the text as follows: Ackeley et al [1] and Hebb [2]. The acknowledgments should go in me special section, which follows the text but precedes the references. All figures should be prepared and included as PostScript (PS) files, and enclosed with the LaTeX-source file on the diskettes. References [1] D.H. Ackeley, G.E. Hilton and T.J. Sejnovski, A learning algorithm for Boizmann machine, Cognitive Science, 62 (1985), 147-169. [2] D.O. Hebb, Organization of Behavior, Wiley, New York (1949). Subscription Rate (4 issues): Library/Inst: USD 120; personal: USD 60; (Add US $ 20 for express mail). ISSN 1311–8080 Ordering Information All payments are by bank cheques in favour of Drumi Bainov. The bank cheques in USD must be sent to the following address: Drumi Bainov, P.O.Box 45, Sofia 1504, Bulgaria.