Personal data


Education, scientific degrees


Membership

Research interests
Teaching and administrative experience

Courses of Lectures


Publications

Monographs, Dissertation, Thesis

  1. Sl.Shtrakov, On the Dominating and Annuling Sets of Variables for Functions, Sofia, SNS in Mathematics, 24.06. 1986 (in Bulgarian), (Ph.D. Thesis), p.156 .
  2. Sl.Shtrakov, Dominating and Annulling Sets of Variables for the Functions, Neofit Rilsky South-West University, Blagoevgrad, 1987, p.179.
  3. R.Pavlov, Sl.Radev and Sl.Shtrakov, Mathematical Foundations of Informatics, Neofit Rilsky South-West University, 1997 (in Bulgarian), p.265.
  4. Sl.Shtrakov, Separability in Algebras of Functions, Terms and Tree Automata, Sofia, SNS in Informatics and Math. Modeling, 17.12. 2007 (in Bulgarian), (Dissertation for Dr.Sc.) Summary (Contents) (in Bulgarian), p.244.

Text-books

  1. K.Chimev, D. Ananieva, Al. Todorov, I. Giudzhenov, M. Aslancky and Sl.Shtrakov, Exercises in Mathematics ,Neofit Rilsky South-West University, 1980, (in Bulgarian), p.483.
  2. K.Chimev, Sl Shtrakov and M. Aslancky, Mathematics ,Neofit Rilsky South-West University, 1985, (in Bulgarian), p.208.
  3. K. Chimev and Sl.Shtrakov, Mathematics with Informatics , Neofit Rilsky South-West University, 1988, (in Bulgarian), p.325.
  4. D. Dureva, St. Jordanova and Sl.Shtrakov, Exercises in Informatics , Neofit Rilsky South-West University, 1992, (in Bulgarian), p.207.
  5. J. Denev and Sl.Shtrakov, Discrete Mathematics, Neofit Rilsky South-West University, 1995, (in Bulgarian), p.279.
  6. Sl.Shtrakov, K. Yordjev, M. Todorova, Exercises in Discrete Mathematics Neofit Rilsky South-West University, 2005, (in Bulgarian), p.180.

Actual research articles

  1. Shtrakov, Sl., Minors of finite operations, Proc. of VII-th Int. Conf. FMNS, 14-18 June 2017 (accepted).
  2. Shtrakov, Sl., Minor complexities of finite operations, Cornell University Library, (arXiv:1611.05633) , p. 24, (2016).
  3. Shtrakov, Sl., Damyanov, I., On the complexity of finite operations Int. J. of Foundations of Computer Science (IJFCS) , Vol. 27, No. 1, (2016), pp.15–38, WSPC, DOI: 10.1142/S0129054116500027 (arXiv:1501.00265).
  4. Shtrakov, Sl., Koppitz, J., Stable varieties of semigroups and groupoids, Algebra Universalis, 2016, Volume 75, Issue 1, 85-106, DOI 10.1007/s00012-015-0359-7, arXiv:1207.6970.
  5. Shtrakov, Sl., Damyanov, I., On the Classification of Boolean Functions, Proc. of the Sixth Int. Sci. Conf. – FMNS2015, (2015), Vol. 1, 125-130. (pdf) .
  6. Shtrakov, Sl.,Symmetric Boolean functions with non-trivial arity gap, Conf. Proc. 4th ICEPU, ESI , pp. 245-248, (2014).
  7. Shtrakov, Sl., Koppitz, J., Congruences and reduction systems in stable varieties, Proc. of V-th Int. Conf. FMNS, 12-16 June 2013 , vol.1, pp. 121-128.
  8. Shtrakov, Sl., Koppitz, J., Finite symmetric functions with non-trivial arity gap, Journal of Computing, Serdica , Vol. 6, Numb. 4, (2012), pp.419-436, (arXiv:1009.4828)
  9. Shtrakov, Sl., Koppitz, J., Kovachev, D., On separable sets in finite functions with nontrivial arity gap, Proc. of IV-th Int. Conf. FMNS, 8 - 11 June, vol.1, 2011, pp. 91-96, MR2868540.
  10. Kovachev, D., Shtrakov, Sl., On Some Algebraic Structures, Proc. of IV-th Int. Conf. FMNS, 8 - 11 June, vol.1, 2011, pp. 44-49, MR2868533.
  11. Shtrakov, Sl., Koppitz, J., On finite functions with non-trivial arity gap, Discussiones Mathematicae - General Algebra and Applications, vol.30, (2010), pp. 217-245, Zbl 05983754, MR2814095, (arxiv:0810.2279).
  12. Shtrakov, Sl., Essential variables and positions in terms, Algebra Universalis, Vol. 61, Issue 3-4, (2009), pp. 381-397, DOI 10.1007/s00012-009-0023-1, Zbl 05652295, MR2565860 (2011a:08008),
  13. Shtrakov, Sl., On the number of functions in a class of k-valued logic, (pdf) Proc. of III-th Int. Conf. FMNS, 3 - 7 June, 2009, pp. 22-26, MR2838710.
  14. Shtrakov, Sl., On a class of functions in finite algebras, (pdf) Proc. of VI Int. Workshop on Optimal Codes and Related Topics, (OC-2009), June 16 - 22, 2009, Varna, BULGARIA , pp. 168-172.
  15. Shtrakov, Sl., Essential arity gap of Boolean functions, , Journal of Computing, Serdica vol.2, Numb. 3, 2008, pp. 249-266, Zbl 1170.06005, MR2489631 (2010c:06023) (arXiv:0808.3892).
  16. Shtrakov, Sl., Multi-Solid Varieties and Mh-transducers, Journal of Algebra and Discrete Mathematics, (Abstract, pdf), Numb. 3 (2007) , pp. 113-137, Zbl 1164.08310, MR2423702, (2009b:08009) (arXiv:math/0702454).
  17. Denecke, K., Koppitz, J., Shtrakov, Sl., Multi-Hypersubstitutions and Colored Solid Varieties, Journal of Algebra and Computation, Vol. 16, No. 4 (2006), pp. 797-815 Zbl 1106.08003, MR 2258839 (2007f:08003), (arXiv:0811.4764).
  18. Koppitz, J., Shtrakov, Sl., On mappings of terms determined by hypersubstitutions, (Abstract, pdf) , Journal of Algebra and Discrete Mathematics, No 3, Jul./Sep. (2005), pp. 18-29, Zbl 1093.20030, MR 2237892 (2007i:20094), (arXiv:0811.3325).
  19. Shtrakov, Sl., Denecke, K., Essential Variables and Separable Sets in Universal Algebra, ( Abstract, pdf ), Multiple-Valued Logic, An International Journal, 2002, vol. 8(2), pp. 165-181, Zbl 1022.08002, MR1957651 (2003k:08005), (arXiv:0812.1979).
  20. Damyanov, I., Shtrakov, Sl., Essential inputs and minimal tree automata, (Abstract, pdf), Discrete mathematics and applications (Bansko, 2001), pp. 77-85, Res. Math. Comput. Sci., 6, South-West Univ., Blagoevgrad, 2002, Zbl 1024.68069, MR 1 928 414 (2003h:68089), (arXiv:cs/0702136).
  21. Shtrakov, Sl., Tree automata and essential subtrees, (Abstract, pdf), Discrete mathematics and applications (Bansko, 2001), pp. 51-59, Res. Math. Comput. Sci., 6, South-West Univ., Blagoevgrad, 2002, Zbl 1021.68059, MR 1 928 411 (2003i:68092), (arXiv:cs/0702137).
  22. Denecke, K., Koppitz, J., Shtrakov, Sl., The depth of a hypersubstitution, (Abstract, pdf), Journal of Automata, Languages and Combinatorics, 6 (2001), No. 3, pp. 253-262, MR1879769 (2003b:08001), (arXiv:0811.4762).
  23. Shtrakov, Sl., Tree automata and essential input variables, (Abstract, pdf), Contributions to general algebra, 13 (Velké Karlovice, 1999/Dresden, 2000), pp. 309-319, Heyn, Klagenfurt, 2001, MR1854595 (2002j:68058), Zbl 0986.68071, (arXiv:cs/0702129).
  24. Shtrakov, Sl., Shtrakov, Vl., Tree Automata and Separable Sets of Input Variables, ( Abstract, pdf), IC, FILOMAT 2001, University of Nis, Yugoslavia , 2001, pp. 61-69, Zbl 1053.68062, MR 2105097 (2005g:68106), (arXiv:cs/0702123).
  25. Shtrakov, Sl., Separable sets of variables and $s$-systems, Discrete mathematics and applications (Blagoevgrad, 1994), ed. Sl.Shtrakov and I. Mirchev, pp. 61-67, Res. Math., 5, Neofit Rilsky South-West University, Blagoevgrad, 1995, MR1331850 (96c:04002).
  26. Shtrakov, Sl., On the Mutually Dominating and Connected Sets of Variables, Discrete mathematics and applications, (1993), ed. K.Chimev and Sl.Shtrakov, Neofit Rilsky South-West University, Blagoevgrad, pp.64-72.
  27. Shtrakov, Sl., On some transformation groups in $k$-valued logic, General algebra and applications (Potsdam, 1992), pp. 225-237, Res. Exp. Math., 20, Heldermann, Berlin, 1993, MR1209902 (94b:03048), Zbl 0793.03023.
  28. Shtrakov, Sl., Separability and Dominance of Sets of Variables for the Functions, Neofit Rilsky South-West University, Year-book (Math.), Blagoevgrad, vol. 7, book 2, 1990, pp.63-72.
  29. Mirtchev, Iv., Shtrakov, Sl., Strongly dominating sets of variables, Közl. MTA Számitástech. Automat. Kutató Int. Budapest, 1988, no. 39, pp. 121-129, MR0987344 (90a:26022), Zbl 0698.04004.
  30. Shtrakov, Sl., Extremal subsets and coverings of the sets of variables for the functions, Közl. MTA Számitástech. Automat. Kutató Int. Budapest, 1988, no. 38, pp. 27-35, MR0963402 (89g:04003), Zbl 0651.04002.
  31. Chimev, K. N., Giudjenov, I. D., Shtrakov, Sl. Vl., Aslanski, M. S., Separable and dominating sets of variables for the functions, Mathematics and mathematical education (in Bulgarian) (Sunny Beach, 1987), pp. 61-71, Bulgar. Acad. Sci., Sofia, 1987, MR 949 933,   Zbl 0641.94024.
  32. Shtrakov, Sl., Inseparable Sets and Their s-Subsets of Variables, Neofit Rilsky South-West University, Year-book (Math.), Blagoevgrad, vol. 5, book 1, 1988, pp.25-49.
  33. Shtrakov, Sl., On the dominating sets of variables for the functions, Mathematics and mathematical education (in Bulgarian), (Sunny Beach, 1987), pp. 563-568, Bulgar. Acad. Sci., Sofia, 1987, MR0949977 (89e:04007).
  34. Shtrakov, Sl., Dominant sets of variables of functions and algorithms for obtaining them. (in Bulgarian) University Annual, Applied Mathematics, Sofia, 22 no. 1, pp. 173-180 (1987), MR0948553 (89e:04006).
  35. Chimev, K. N., Shtrakov, Sl., Generalized orders of variables and $\epsilon$-equivalence in some algebras of functions, (in Bulgarian), University Annual, Applied Mathematics, Sofia, 22 no. 1, pp. 151-158 (1987), MR0948550 (89e:04003).
  36. Shtrakov, Sl., On the separable and annuling sets of variables for the functions, Közl. MTA Számitástech. Automat. Kutató Int. Budapest, 35, pp. 147-168 (1986), MR0882311 (88e:04002), Zbl 0611.04001.
  37. Shtrakov, Sl., On the C-separable and dominant sets of variables of functions, Mathematics and education in mathematics, Proc. 15th Spring Conf., Sunny Beach/Bulg. 1986, pp. 345-350 (1986), Zbl 0604.94010.
  38. Chimev, K., Shtrakov, Sl., On the dominant sets and separable pairs of essential variables of functions, University Annual, Applied Mathematics, Sofia, 21, no. 3, 145-151 (1986), (in Bulgarian). MR0906951 (88h:04003).
  39. Shtrakov, Sl., On the Annulator Sets of Variables for the Functions, MTA SzTAKI Tanulmanyok, Budapest, 182(1986), pp. 43-50, MR0929889 (89c:26025).
  40. Shtrakov, Sl., On the Dominant Sets of Variables for the Functions, MTA SzTAKI Tanulmanyok, Budapest, 182(1986), pp. 37-42, MR0929888 (89c:26024).
  41. Shtrakov, Sl., Mutually Dominating Sets of Variables for the Functions, MTA SzTAKI Tanulmanyok, Budapest, 182(1986), pp. 51-76, MR 0929890 (89b:26019).
  42. Shtrakov, Sl., On the $c$-separable and dominant sets of variables for the functions, Közl. MTA Számitástech. Automat. Kutató Int. Budapest, No. 32, (1985), pp. 155-161, MR0810747 (87e:06032).
  43. Shtrakov, Sl., On some transformations in the $K$-valued logic, Mathematics and mathematical education (Sunny Beach, 1985), pp. 305-309, Bulgarian Academy of Science, Sofia, 1985, MR0805369 (87c:03045), Zbl 0592.03012.
  44. Shtrakov, Sl., The Annulling Sets of Essential Variables of the Functions, Neofit Rilsky South-West University, Year-book (Math.), vol. 1, book 1, 1984, pp. 91-97.


Conferences
Organizing or Editing of the Proceedings

  1. VII-th Int. Conf. FMNS, (FMNS-2017), 14 – 18 June 2017, Blagoevgrad, BULGARIA, Paper's title: Minors of finite operations.
  2. VI-th Int. Conf. FMNS, (FMNS-2015), 10 – 14 June 2015, Blagoevgrad, BULGARIA, Paper's title: On the classification of Boolean functions.
  3. V-th Int. Conf. FMNS, (FMNS-2013), 12 - 16 June 2013, Blagoevgrad, BULGARIA, Paper's title: Congruences and reduction systems in stable varieties.
  4. 7th International Conference on Discrete mathematics and applications (ICDMA 7) held in Bansko, June 17- 20, 2004, Edited by Sl. Shtrakov and K. Denecke. Research in Mathematics and Computer Sciences, 7. South-West University, Blagoevgrad, 2005, Abstracts ISBN: 954-680-363-4, MR2181448.
  5. Invited session "Universal Algebra, Tree Automata and XML-Data" at the 7th World Multi Conference on Systemics, Cybernetics and Informatics (SCI 2003). July 27 - 30, 2003, Orlando, Florida, USA Sheraton World
  6. 6th International Conference on Discrete mathematics and applications (ICDMA 6) held in Bansko, August 31-September 2, 2001. Edited by Sl. Shtrakov and K. Denecke. Research in Mathematics and Computer Sciences, 6. South-West University, Blagoevgrad, 2002. viii+218 pp. ISBN: 954-680-219-0 Abstracts
    MR 1928405,
  7. International Conference on Discrete mathematics and applications (ICDMA 5) held in Blagoevgrad, September 12-16, 1994. Edited by Sl. Shtrakov and Iv. Mirchev . Research in Mathematics, 5. Neofit Rilsky South-West University, Blagoevgrad, 1995. 256 pp. ISBN: 954-680-001-5
    MR 95m:00019,
  8. International Conference on Discrete mathematics and applications (ICDMA 3) held in Blagoevgrad, September 08-11, 1992. Edited by K. Chimev and Sl. Shtrakov . Research in Mathematics, 3. Neofit Rilsky South-West University, Blagoevgrad, 1993. 151 pp.
  9. International Conference on Discrete mathematics and applications (ICDMA 2) held in Predela, June 05-10, 1990. Edited by Sl. Shtrakov. Research in Mathematics, 2. Neofit Rilsky South-West University, Blagoevgrad, 1990. 105 pp.


Participating in Conferences with Presentations

  1. Arbeitstagung Allgemeine Algebra (AAA89), Institute of Algebra at Technische Universitat Dresden, February 26 - March 01, 2015, Dresden, Germany, Paper's title: Separable sets and ODDs of finite functions, Abstract
  2. Conf. 125 Years of Math. and Natural Sciences at Sofia Uni. "St. Kliment Ohridski", 5-7 December, 2014, Paper's title: On the Complexity of Finite Valued Functions Abstract
  3. Seminar Coding theory , 20-23 November, 2014, V. Tarnovo, Paper's title: On the Complexity of Finite Valued Functions ( Abstract, pdf )
  4. Arbeitstagung Allgemeine Algebra ( AAA87 & CYA28), Linz, Feb 7-9, 2014, Paper's title: Stable Varieties of Semigroups, Abstract
  5. Arbeitstagung Allgemeine Algebra (AAA84), Institute of Algebra at Technische Universitat Dresden, June 8-10, 2012, Paper's title: Stable varieties of semigroups, Abstract
  6. IV-th Int. Conf. FMNS, (FMNS-2011), 8 - 11 June, 2011, Blagoevgrad, BULGARIA, Paper's title: On separable sets in finite functions with nontrivial arity gap.
  7. Mathematical Conference 2010, Dedicated to Professor Gorgi Cupona, Ohrid, Macedonia, September 10-13, 2010 , Paper's title: Symmetric Functions with Non-trivial Arity Gap Abstract.
  8. Sixth International Workshop on Optimal Codes and Related Topics, (OC-2009), June 16 - 22, 2009, Varna, BULGARIA , Paper's title: On a class of functions in finite algebras, Abstract.
  9. Third International Scientific Conference (FMNS-2009), 03 - 07.06.2009, Blagoevgrad, BULGARIA, Paper's title: On the number of functions in a class of $k$-valued logic, Abstract.
  10. Arbeitstagung Allgemeine Algebra (AAA77), University of Potsdam, March 20-22, 2009, Paper's title: On the essential arity gap of finite valued functions, Abstract.
  11. IV Congress of the Mathematicians of Republic Macedonia (SMMK08) Struga, 19-22.10.2008, Paper's title: Essential Arity Gap of Boolean Functions, Abstract.
  12. 11-th International Workshop on Algebraic and Combinatorial Coding Theory ACCT08, June 16-22, 2008, Pamporovo, Paper's title: Essential Arity Gap of Finite Valued Functions.
  13. Arbeitstagung Allgemeine Algebra (AAA75), Darmstadt University of Technology, November 2–4, 2007, Paper's title: Multi-solid varieties, Abstract
  14. Arbeitstagung Allgemeine Algebra (AAA69), University of Potsdam, Germany, March 18-20, 2005, Paper's title: Coloured Terms and Multihyper-substitutions , Abstract
  15. Arbeitstagung Allgemeine Algebra (AAA68), University of Dresden, Germany, June, 10-13,2004, Paper's title: Recursive Coloration of Trees, Abstract
  16. Arbeitstagung Allgemeine Algebra (AAA67), University of Potsdam, Germany, March 26-28, 2004, Paper's title: On the colouration of terms, Abstract
  17. Arbeitstagung Allgemeine Algebra (AAA65) Potsdam ,Germany,  20-23.03.2003   Paper's title: All Input Variables Are Essential for Almost All Trees and Logical Tree Automata (Abstract)
  18. Arbeitstagung Allgemeine Algebra (AAA63) Kaiserslautern ,Germany,  22-24.02.2002   Paper's title: Sequences of Hypersubstitutions and Coloring (Abstract)
  19. International Conference on Galois Connections (ICGC2001) , Potsdam, Germany,  15-18.03.2001 Paper's title:  Tree Automata and Essential Subtrees(Abstract)
  20. Arbeitstagung Allgemeine Algebra (AAA61) Darmstadt,Germany,  02-04.02.2001.  Paper's title: Algorithms for Depth and Size of Hypersubstitutions
  21. International Conference Filomat 2001, Nis, Yugoslavia , 26.08-30.08.2001 Paper's title:  Tree Automata and Computational Complexity.
  22. Arbeitstagung Allgemeine Algebra (AAA60) Dresden,Germany  22-25.06.2000  Paper's title: Tree Automata and Essential Input Variables (Abstract)
  23. Arbeitstagung Allgemeine Algebra (on occasion of the 70th birthday of H.-J.Hoehnke) (AAA 52) University of Potsdam, Campus Am Neuen Palais, Germany 03-06.06.1996.  Paper's title: Dominating and Connected Sets of Variables
  24. Arbeitstagung Allgemeine Algebra (AAA43) University of Potsdam,Campus Golm,Germany,  31.01.1993-02.02.1993 Paper's title: On Some Transformation Groups in k-Valued Logic.



Coordinator from the South-West University of Projects and Cooperation

University Study Projects

  1. TEMPUS JEP 1728 "University Network for Cooperation and Development of Artificial Intelligence and Modern Information Technologies Education" , 1992-1994
  2. TEMPUS SJEP 7272 "University Network for Information Technologies Education in Economic, Social and Political Sciences, Business and Humanities", 1994-1997
  3. TEMPUS CME 01006 "Intra- and Inter-university Services Support", 1995
  4. TEMPUS SJEP 11087 " Modular Education in Mathematics and Informatics" , 1996-1999

Scientific Projects

  1. Centre of Excellence for Applications of Mathematics, Stability pact (via DAAD) project with Universities of Duisburg, Skopie, Cluj, Novi Sad, Nish, Plovdiv and Sofia, 2001-2009
  2. Annual projects for co-operation with DAAD (Germany) and University of Potsdam- since 1993
  3. Moscow State University (3 month-specialization) 1984
  4. Bulgarian Academy of Science- 1991-1999
  5. Computer Science Department of Hungarian Academy of Science, (specialization) 1993
  6. International Training Center at Jerusalem,Israel "Education for Science and Technology", (seminar, 1 month) 1998
  7. "Discrete Mathematics and Applications", part of Stability pact, founded by Alexander von Humboltd foundation, 2001,2004

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