CV/Professional Life

Education

  • Ph.D., Department of Mathematics, University of Pennsylvania, Philadelphia, USA, 1987
    Thesis: “Some Extremal Problems for Graphs with Fixed Numbers of Vertices and Edges,”
    Advisor: Professor H.S. Wilf
  • M.S. (Diploma), Mathematics, Kiev State University, Kiev, USSR, 1975
    Thesis: “Arrangements of Some Geometrical Groups in Symmetric Groups”
    Advisors: Professors L.A. Kaluznin and M.H. Klin

Research Interests

Combinatorics, Graph Theory, Algebra, Geometry.
I am interested in other topics and willing to work on any problem I like.

Service Outside the Department

I am a member of the Editorial Board of the Electronic Journal of Combinatorics .

Employment

  • Visiting Professor, University of Pennsylvania, Spring, 2001 (sabbatical)
  • Visiting Researcher, DIMACS, Rutgers University, Fall 2000 (sabbatical)
  • Professor, Department of Mathematical Sciences, University of Delaware, since 9/1998
  • Associate Professor, Department of Mathematical Sciences, University of Delaware, 9/1993-8/1998
  • Visiting Researcher, RUTCOR, Rutgers University, 9-12/ 1993 (sabbatical)
  • Assistant Professor, Mathematical Sciences, University of Delaware, 9/1987-8/1993
  • Lecturer (part time), Haverford College, Spring 1987
  • Lecturer and TA , University of Pennsylvania, 9/1980-5/1987
  • Lecturer (part time), Spring Garden College of Philadelphia, 1984-1986
  • Lecturer (part time), Philadelphia Community College, 1981-1982
  • Actuarial Assistant, General Accident Ins.Co., 2/1982-7/1983
  • Teacher of Mathematics, Dynamic Springs Private School, Media, PA, Summer 1988
  • Teacher of Mathematics, Mathematics and Physics Boarding High School at Kiev State University, Kiev, USSR, 1975–1979

Research Advising

    • Dr.  Vladislav Taranchuk (Ph.D. — 5/2023).
    • Dr. Melissa Fuentes (Ph.D. — 5/2021),   Villanova University, PA.
    • Dr. Benjamin Nassau (Ph.D. — 8/2020),   Rowan University, NJ.
    • Dr. Lorinda Leshock (Ph.D. — 8/2020),   Data Scientist, R&D West Pharmaceutical Services, Exton, PA.
    • Dr. Shuying Sun (Ph.D. — 5/2017, co-advised with Dr. N. Bhatnagar).   Microsoft, Seattle, WA.
    • Dr. James Alexander (Ph.D. — 5/2016),  Synopsys Inc., Mountain View, CA.
    • Dr. Ye Wang (8/2013 — 8/2014, visiting graduate student from Tongji University, China. Ph.D. — 2015).  Harbin Engineering University, China.
    • Dr. Alexandr Kodess (Ph.D. — 8/2014), Farmingdale State College, NY.
    • Dr. Brian Kronenthal (Ph.D. — 5/2013), Kutztown University, Kutztown, Pennsylvania.
    • Dr. Bryan Petrak (Ph.D. — 6/2012, co-advised with Dr. G.L. Ebert). Boeing Corp., Oklahoma City, Oklahoma.
    • M.A. Thesis advisor for  Dr. Spencer Tofts (2010-2011), Ph.D. from the University of Pennsylvania in 2016. Google, Pittsburg, PA.
    • Undergraduate Research Program for Dr. Michael Tait (Summer, Fall 2009). Ph.D. in Mathematics from UC San Diego.
    • Dr. Bill Cuckler (9/2006 — 9/2008),  post doctoral student. DOD.
    • Undergraduate Research Program for Dr. Alison Gordon Lynch (Summer 2006). Ph.D. in Mathematics from University of Wisconsin.
    • Undergraduate Research Program for Robert DeMarco (Summer 2005 — Spring 2006). Ph.D. in Mathematics from Rutgers University.
    • Dr. Jason Williford (Ph.D. — 6/2004), University of Wyoming, Laramie, Wyoming.
    • Dr. Vasyl Dmytrenko (Ph.D. — 6/2004), Temple University, Philadelphia, PA. 1961 — 2013.
    • Dr. Sven Reichard (Ph. D. — 6/2003, (co-advised with Dr. M.H. Klin).
    • Dr. Raymond Viglione (Ph.D. — 6/2002 ), Kean University, Union, New Jersey.
    • Undergraduate Research Program and Honor Thesis (co-advised with Dr. G.L. Ebert) for   David Kravitz (graduated in 5/2000).
      Ph.D. from Carnegie-Mellon University.
    • Dr. Owen Byer (Ph.D. — 5/1996 ), Eastern Mennonite University, Harrisonburg, Virginia.
    • Undergraduate Research Program and Honor Thesis (co-advised with Dr. W. Li) for  Ryan Martin (graduated in 5/1995). Ph.D. from Rutgers University.
      Dr. Ryan Martin, Iowa State University, Ames, Iowa.
    • M.S. Thesis advisor for  Alexander Schliep (graduated in 2/1994 ). Ph.D. from Max Plank Institute.
      Dr. Alexander Schliep , Chalmers — Gothenburg University.
    • Dr. Gene Fiorini , (Ph.D. — 6/1993), DIMACS, Rutgers University, Piscataway, New Jersey.
    • Undergraduate Research Program for  Samuel Stump (Summer 1992).

    Teaching

    University of Delaware:

    Undergraduate Courses:

    • Discrete Mathematics I (M210)
    • Calculus with Applications (M221)
    • Finite Mathematics with Applications (M230)
    • Calculus I (M241), Calculus II (M242 – with Maple)
    • Calculus III (M243 – in Computer Classroom with Maple)
    • ODE with Applications (M302 -in Computer Classroom with Maple)
    • Discrete Mathematics II (M315)
    • History Of Mathematical Ideas (M308)
    • Linear Algebra (M349)
    • Graph Theory (M389)
    • Abstract Algebra (M450/M451)
    • Ideas of Geometry (Summer College, Special Programs)
    • Geometry (M540)
    • Geometry (a special summer course for DPI Critical Curriculum Program)
    • Discrete Mathematics (a special summer course for DPI Critical Curriculum Program)
    • Coding Theory (M567)

    Graduate Courses:

    • Foundations of Mathematics I, II (M567) (for Ph.D. Program in Mathematics Education)
    • Abstract Algebra (M650)
    • Vector Spaces (M672)
    • Combinatorics I (M688)
    • Combinatorics II (M689)
    • Methods of Linear Algebra in Combinatorics (Thematic Seminar – M699)
    • Group Theory with Applications (M845)
    • Field Theory with Applications (M846)
    • Asymptotic Theory of Designs (Topic Course – M867)
    • Extremal Combinatorics (M885)

    Reading Courses:

      • Selected topics in Abstract Algebra (three different courses)
      • Finite Non-Desaguesian planes
      • Finite Fields
      • Finite Geometries
      • Methods of Linear Algebra in Graph Theory
      • Algebraic methods in Combinatorics
      • Topics in Combinatorics and Graph Theory (five different cources)
      • Extremal Graph Theory
      • Probabilistic Methods in Combinatorics and Graph Theory
      • Nowhere-zero flows in graphs

    University of Pennsylvania

      • as Instructor:
        • Algebra and Functions; Ideas of Mathematics and Computer; Introduction to Mathematics II; Calculus I, II, III; Advanced Calculus; Linear Algebra; Summer Enrichment Program for Gifted Children (3 different courses)

    as Teaching Assistant:

        • Calculus I – Computer Section (Fortran), Calculus I, II – Computer Sections (Basic) Real Analysis; Ordinary Differential Equations

    Haverford College:

        • Problem Solving in Pascal

    Spring Garden College of Philadelphia:

          • Precalculus I, II; Calculus I, II

    Philadelphia Community College:

    • Basic Arithmetic I, II; Basic Algebra and Mathematical Concepts

Math – Physics Boarding High School at the Kiev State University:

    • Three year special course in mathematics (included regular and advanced topics of the high-school curriculum in algebra, geometry and calculus; number theory; abstract algebra; geometric transformations; preparation of the school teams for mathematical olympiads.

Invited Talks at Conferences

  • DIMACS Workshop on Expanding Graphs and Applications, Princeton University, Princeton, NJ, May 11–14, 1992.
  • AMS meeting, Special Section on Extremal Combinatorics and Graph Theory, DeKalb, IL, May 1993.
  • The International Conference “Algebra and Combinatorics: Interactions and Applications”, Konigstein, Germany, March 1994.
  • The 6–th International Conference on Formal Power Series and Algebraic Combinatorics, Rutgers University, New Brunswick, NJ, May 1994.
  • The The NSF/CBMS Research Conference on Eigenvalues and Combinatorics, CSU, Fresno, CA, June 1994.
  • Invited Speaker at the award ceremony for The Delaware Mathematical League, Dover, DE, March 1995.
  • A Combinatorics and Graph Theory Conference in Honor of Herb Wilf’s 65th birthday, University of Pennsylvania, Philadelphia, Pa, June 1996.
  • Workshop on Extremal Combinatorics, Mathematical Sciences Research Institute, Berkeley, November 1996.
  • International Colloquium on Extremal Graph Theory, dedicated to the memory of Paul Erdos, Balatonlelle, Hungary, July 1997.
  • AMS meeting, Special Section on Combinatorics and Graph Theory, Louisville, Kentucky, March 1998.
  • DIMACS Research & Education Institute 1998: Graph Theory and Combinatorial Optimization, DIMACS Center, Rutgers University, Piscataway, NJ, July, 1998.
  • First Annual K-12 Mega-Conference on Discrete Mathematics, DIMACS Discrete Math/Theory of Computing Seminar, DIMACS Center, Rutgers University, Piscataway, NJ, December, 1998 (two 2.5 hour workshops for high school teachers).
  • Joint CMS-AMS meeting, Special Section on Extremal Combinatorics and Graph Theory, Queen’s University, Kingston, Canada, December, 1998.
  • AMS meeting, Special Section on Combinatorics and Graph Theory, SUNY, Buffalo, New York, April 1999.
  • DIMACS Mathematics Series, AT & T, Shannon Laboratory, Florham Park, NJ, October 2000.
  • AMS meeting, Special Section on Extremal Combinatorics, University of Indiana, Bloomington, Indiana, April 2003.
  • AMS meeting, Special Section on Finite Geometries, University of Colorado, Boulder, Colorado, October, 2003.
  • AMS meeting, Special Section on Extremal Combinatorics, Vanderbilt University, Nashville, Tennessee, June, 2004.
  • AMS meeting, Special Section on Extremal Combinatorics, Northwestern University, Evanston, Illinois, October 2004.
  • WaterMellon Workshop on Extremal Graph Theory, Carnegie Mellon University, Pittsburgh, Pennsylvania, May, 2005.
  • AMS meeting, Special Section on Extremal and Probabilistic Combinatorics, University of Arkansas, Fayetteville, Arkansas, November, 2006.
  • EXCILL: Extremal Combinatorics at Illinois, University of Illinois, Urbana-Champaign, Illinois, November, 2006.
  • AMS meeting, Special Section on Algebraic and Extremal Combinatorics, Davidson College, North Caroline, March 2007.
  • Workshop on Extremal Combinatorics, Alfred Renyi Institute of Mathematics, Budapest, Hungary, June 2007.
  • WaterMellon Workshop on Extremal Graph Theory II, University of Waterloo, Canada, June, 2009.
  • Rocky Mountain Discrete Mathematics Day, University of Colorado at Denver, Denver, Colorado, June, 2009.
  • AMS Central Section meeting, Special Section on Extremal and Probabilistic Combinatorics, Macalester College, St Paul, Minnesota; April 2010.
  • Spring 2010 AMS Eastern Sectional meeting, Special Section on Graph Theory, NJIT, Newark, New Jersey; May 2010.
  • Workshop on Linear Algebra Techniques in Combinatorics and Graph Theory, Banff International Research Station, Banff, Alberta, Canada; January-February 2011.
  • Rocky Mountain Discrete Mathematics Day, University of Wyoming, Laramie, Wyoming; June 2013.
  • The 6th International Workshop on Optimal Network Topologies,  Bratislava, Slovakia; June-July 2014.
  • 28th Cumberland Conference on Combinatorics, Graph Theory and Computing University of South Carolina, Columbia, SC; May 2015;
  • The Third Annual Conference for the Exchange of Mathematical Ideas, Department of Mathematics, University of Mary Washington, Fredericksburg, VA, USA; June 2015.
  • Discrete Mathematics Days 2016, The Fields Institute for Research in Mathematical Sciences, Carleton University, Ottawa, Canada; May 2016
  • The 7th International Workshop on Optimal Network Topologies,  Tsinghua Sanya International Mathematics Forum, Sanya, China. July 2016.
  • Fall Western Sectional Meeting of the AMS, Special Section on Algebraic Combinatorics, University of Denver, Denver, Colorado; October 2016.
  • Conference on Algebraic and Extremal Graph Theory (AEGT), University of Delaware, Delaware; August, 2017. The conference photograph is: here.
  • CanaDAM 2019, Special Minisymposium on Extremal Combinatorics, Simon Fraser University, Vancouver, Canada; May 2019.
  • Workshop on Extremal Graphs arising from Designs and Configurations, Banff International Research Station, Banff, Alberta, Canada; May 2023.
  • International Workshop on Optimal Network Topologies, ICMS, Bayes Centre, Edinburgh, UK; July 2023.

Other conferences, contributed talks, colloquia, seminars, lectures, professional visits

  • Two talks at Mathematical Colloquium in University of Kiev, 1974–1975.
  • Two talks at the Kiev High School Teachers Seminar, Kiev, 1977.
  • AMS Meeting, Fairfield, CT, October, 1983.
  • ICM-86, Berkeley, CA, August, 1986.
  • Lecture for High School Students: “Why Math?”, April 1986.
  • Four Lecture Seminar for Elementary School Teachers, Abington, PA, October 1987.
  • Conference on Probabilistic Methods in Combinatorial Optimization, Baltimore, MD, June 1987.
  • RUTCOR Conference, Newark, NJ, November, 1987.
  • AMS–MAA Meeting, Atlanta, GA, January, 1988; contributed talk.
  • Nineteenth Southeastern International Conference on Combinatorics, Graph Theory and Computing, LSU, Baton Rouge, LA, February, 1988; contributed talk.
  • Third Advanced Research Institute on Discrete Applied Mathematics, RUTCOR, New Brunswick, NJ, May, 1988.
  • Lecture for general public: “What is Mathematics?”, October 1988.
  • Sixth International Conference on Graph Theory and Applications, Western Michigan University, Kalamazoo, MI, June, 1988; contributed talk.
  • AMS–MAA Meeting, Phoenix, AZ, January, 1989
  • Twentieth Southeastern International Conference on Combinatorics Graph Theory, Computing, FAU, Boca Raton, FL, February, 1989; contributed talk.
  • A talk at the Combinatorics Seminar at George Washington University, Washington, D.C., April, 1989
  • The Capital City Conference on Combinatorics and Theoretical Computer Science, The George Washington University, Washington, D.C., May, 1989; contributed talk.
  • The Fourth Advanced Research Institute on Discrete Applied Mathematics, RUTCOR, New Brunswick, NJ, June, 1989; contributed talk.
  • Joint Summer Research Conference on Probabilistic and Analytic Methods in Discrete Mathematics, Humbolt State University, Arcata, CA, June, 1989.
  • AMS–MAA Meeting, Louisville, KY, January, 1990.
  • Twenty–first Southeastern International Conference on Combinatorics, Graph Theory and Computing, FAU, Boca Raton, FL, February 1990.
  • A talk at the Combinatorics Seminar at George Washington University, Washington, D.C., March 1990.
  • Fifth Advanced Research Institute on Discrete Applied Mathematics, RUTCOR, New Brunswick, NJ, May, 1990; contributed talk.
  • Fifth SIAM Conference on Discrete Mathematics, Atlanta, GA, August 1990; Organized (with other members of Combinatorics/Algebra Group, UD) and chaired a mini symposium on “Irregular Networks”, which took place during the conference.
  • ICM–90, Kyoto, Japan, August 1990; contributed talk.
  • AMS–MAA Meeting, San Francisco, CA, January 1991. Attended a two day mini course on “Probabilistic Methods in Combinatorics”, which took place before the meeting
  • Winter Meeting of the EPADEL Section of the MAA, U.D., Newark, DE, January, 1991.
  • Twenty–second Southeastern International Conference on Combinatorics, Graph Theory and Computing, LSU, Baton Rouge, LA, February 1991; contributed talk.
  • Sixth Advanced Research Institute on Discrete Applied Mathematics, RUTCOR, New Brunswick, NJ, June, 1991; contributed talk.
  • Fall Meeting of the EPADEL Section of the MAA, Drexel University, Philadelphia, PA, November, 1991.
  • Twenty–third Southeastern International Conference on Combinatorics, Graph Theory and Computing, FAU, Boca Raton, FL, February 1992; contributed talk.
  • Colloquium Speaker at the Department of Mathematics, George Washington University, Washington, D.C., April 1992.
  • Seventh Advanced Research Institute on Discrete Applied Mathematics, RUTCOR, New Brunswick, NJ, May–June, 1992; contributed talk.
  • Seventh International Conference on Graph Theory and Applications, Western Michigan University , Kalamazoo, MI, June, 1992; contributed talk.
  • Sixth SIAM Conference on Discrete Mathematics, University of British Columbia, Vancouver, Canada, June, 1992; contributed talk.
  • A talk at the Temple Number Theory/Combinatorics/Modular Forms Seminar, Temple University, Philadelphia, November 4, 1992.
  • Holiday Symposium on Lie Group Representations and Combinatorics, Las Cruses, New Mexico, December 1992; contributed talk.
  • 1993 SIAM Annual Meeting, Philadelphia, June 1993; chaired a session on Combinatorics and Graph Theory; contributed talk.
  • The International Conference on Combinatorics, Paul Erd\H os is Eighty, International Conference sponsored by Janos Bolyai Mathematical Society, Keszthely, Hungary, July 1993; contributed talk.
  • A talk at the Combinatorics Seminar at George Washington University, Washington, D.C., December 1993.
  • Colloquium Speaker, RUTCOR, Rutgers University, December 1993.
  • The Seventh SIAM Conference on Discrete Mathematics, Albuquerque, NM, June 1994; contributed talk.
  • Math 301: Implementation of Standards, Teacher’s conference, Ocean City, MD, November, 1994
  • Eight Cumberland Conference on Graph Theory, Combinatorics and Computing, Vanderbilt University, Nashville, TN, April 1995; contributed talk.
  • The 15–th British International Conference on Combinatorics, University of Stirling, Stirling, Scotland, July 1995; contributed talk.
  • Colloquium Speaker, Gettysburg College, Gettysburg, PA, October 1995
  • Twenty–Seventh Southeastern International Conference on Combinatorics, Graph Theory and Computing, LSU, Baton Rouge, LA, February 1996; contributed talk.
  • Colloquium Speaker, Shippensburg University, Shippensburg, PA, March 1996.
  • Eighth International Conference on Graph Theory, Combinatorics, Algorithms and Applications, Western Michigan University , Kalamazoo, MI, June, 1996; contributed talk.
  • A talk at Combinatorics Seminar, Department of Mathematics, Tel Aviv University, Tel Aviv, Israel; January 1997.
  • A talk at a joint meeting of Combinatorics Seminar and The Amitsur Algebra Seminar, Department of Mathematics, Hebrew University, Jerusalem, Israel; January 1997.
  • A talk at Algebra Seminar, Department of Mathematics, Center for Teaching and Technology, Holon, Israel; January 1997.
  • A talk at the Combinatorics Seminar, Department of Mathematics, Technion, Haifa, Israel; January 1997.
  • A talk at Algebra Seminar, Department of Mathematics and Computer Sciences, Bar-Ilan University, Bar-Ilan, Israel; January 1997.
  • Colloquium Speaker, Department of Mathematics and Computer Science, Ben-Gurion University, Beer-Sheva, Israel; January 1997.
  • Twenty-Eigth Southeastern International Conference on Combinatorics, Graph Theory, Computing, FAU, Boca Raton, FL, February 1997; contributed talk.
  • A talk at DIMACS Discrete Math/Theory of Computing Seminar, DIMACS Center, Rutgers University, Piscataway, NJ, February 1997.
  • Colloquium Speaker, Department of Mathematics, Emory University, Atlanta, Georgia; April 1997.
  • The 16–th British International Conference on Combinatorics, Queen Mary and Westfield College, London, July 1997; contributed talk.
  • Fall Meeting of the EPADEL Section of the MAA, University of Pennsylvania, Philadelphia, PA, November 1997.
  • Twenty-Ninth Southeastern International Conference on Combinatorics, Graph Theory, Computing, FAU, Boca Raton, FL, March 1998; contributed talk.
  • Twenty-Third Australian Conference on Combinatorial Mathematics and Combinatorial Computing, University of Queensland, Brisbane, Australia; July 1998; contributed talk.
  • A talk at Number Theory/Cryptology Seminar, Department of Mathematics and Computer Sciences, Macquiry University, Sydney, Australia; July 1998.
  • A talk at Faculty/Student Seminar, Messiah College, Grantham, PA; December 1998.
  • Colloquium Speaker, Department of Mathematics, Lehigh University, Bethlehem, PA; December 1998.
  • KCC-99 (a Combinatorics Conference in Honor of D. Kleitman’s 65th birthday), Department of Mathematics, MIT, Cambridge, MA; August 1999.
  • A talk at Discrete Mathematics Seminar, Department of Mathematics, Princeton University, NJ; March 2000.
  • The Ninth Quadrennial International Conference on Graph Theory, Combinatorics, Algorithms and Applications, June 4-9, 2000, Kalamazoo, MI, USA; contributed talk.
  • The 6th International Conference on Graph Theory, August 28-September 1, 2000, Marseille, France; contributed talk.
  • A talk at Discrete Mathematic Seminar, University of Memphis, Memphis, TN, October, 2000. (A five day visit.)
  • Colloquium Speaker, Department of Mathematics, US Naval Academy, Annapolis, MD; April, 2001.
  • A talk at Combinatorics Seminar, Cambridge University, Cambridge, UK, May, 2001. (A two week visit.)
  • A talk at Discrete Mathematics Seminar, Department of Mathematics, Princeton University, NJ; December 2001.
  • Colloquium Speaker, Department of Mathematics, Drexel University, Philadelphia, PA; January, 2002.
  • Thirty-Third Southeastern International Conference on Combinatorics, Graph Theory, Computing, FAU, Boca Raton, FL, March 2002; contributed talk.
  • A talk at Combinatorics Seminar, Microsoft Research Theory Group, Redmont, WA, May-July, 2002. (One and two week visits.)
  • Mid-Atlantic Center for Mathematics Teaching and Learning Conference, Pennsylvania State University, State College, PA, June 2002.
  • Geometric and Algebraic Combinatorics 2, Oisterwijk, the Netherlands, August 11-16, 2002; contributed talk.
  • A talk at Discrete Mathematics Seminar, Department of Mathematics, Princeton University, NJ; April 2003.
  • Extremal Combinatorics, Conference and Workshop, Renyi Institute of Mathematics, Budapest/Czopak, Hungary, June-July, 2003; contributed talks.
  • Combinatorics in Cambridge (celebrating Bela Bollobas’s 60th birthday), Cambridge UK, August 4-7, 2003.
  • Organized (with David Fleshner) an EPADEL Conference for Undergraduates “Careers in Mathematics”, Gettysbyrg College, Gettysburg, PA; November 2003.
  • A talk at Combinatorics Seminar, Department of Mathematics, University of Illinois at Chicago, IL; December 2003.
  • A talk for the Mathematics Awarness Week at the University of Delaware, Newark, Delaware, April, 2004.
  • A talk at Combinatorics Seminar, Department of Mathematics, University of Pennsylvania, Philadelphia, PA; December 2004.
  • Colloquium Speaker, Department of Mathematics, Iowa State University, Aimes, Iowa; January, 2005.
  • AMS Meeting, Special Section on Coding and Finite Geometries. University of Delaware, Newark, Delaware; April 2005.
  • A talk at Tutte Seminar, Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Canada; April 2005.
  • AMS Meeting, Special Section on Extremal and Probabilistic Combinatorics. Bard College,  Annandale-on-Hudson, New Yourk, USA; October 2005.
  • Lie Groups, Representations and Discrete Mathematics Workshop,  IAS, Princeton, New Jersey, USA; February 2006.
  • Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Canada;  March 2006. (A five day visit.)
  • A talk at Combinatorics Seminar, Department of Mathematics, University of Pennsylvania, Philadelphia, PA;   April 2006.
  • SIAM Conference on Discrete Mathematics, University of Victoria, Victoria, British Columbia, Canada; June 2006 (Co-organizer of minisimposium; contributed talk.)
  • Colloquium Speaker, Department of Mathematics, US Naval Academy, Annapolis, MD; October, 2006.
  • A talk at the Combinatorics Seminar at George Washington University, Washington, D.C.; October 2006.
  • AMS meeting, Special Section on Finite Geometries, Miami University, Oxford, Ohio, March 2007.
  • A talk at the Combinatorics/Geometry Seminar, Department of Mathematics, University of Colorado at Denver, Denver, Colorado, April 2007. (A four day visit.)
  • Colloquium Speaker, Department of Mathematics, University of Mary Washington, Fredericksburg, VA; October, 2007.
  • Colloquium Speaker, Department of Mathematics, University of Miami, Oxford, OH; October, 2007.
  • Additive Combinatorics Workshop, IAS, Princeton, NJ; October-December 2007.
  • Expanders in Pure and Applied Mathematics, IPAM, UCLA, CA; February 2008.
  • A talk at the Combinatorics Seminar, Department of Mathematics, UCSD, La Jolla, CA; March 2008. (A two week visit.)
  • A talk at the Combinatorics Seminar, Department of Mathematics, LSE, London, UK; May 2008. (A four day visit.)
  • A talk at the Combinatorics Seminar, Department of Mathematics, University of Cambridge, UK; May 2008. (A week visit.)
  • A lecture for high school students, Liceum #38, Kiev, Ukraine; May 2008.
  • A talk at the Geometry Seminar, Department of Mathematics, University of Ghent, Ghent, Belgium; June 2008. (A two week visit.)
  • Colloquium Speaker, Department of Mathematics, University of Liege, Belgium; June 2008.
  • The 9th International Conference on Finite Fields and Their Applications, University College Dublin, Ireland, July 2009; contributed talk.
  • Workshop on Exremal and Probabilistic Combinatorics, IPAM UCLA, CA; November 2009.
  • International Conference on Designs, Codes and Geometries in Honor of Gary Ebert on the occasion of his retirement,
    University of Delaware, Lewis, Delaware; March–April 2010. (Co-organized the conference with Qing Xiang.)
  • From A=B to Z=60. Conference in Honor of Doron Zeilberger’s 60-th Birsday, DIMACS, Piscataway, NJ; May, 2010.
  • A talk at the Combinatorics Seminar, Department of Mathematical Sciences, Carnegie Mellon University, Pittsburgh, PA.; November 2010.
  • Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Ontario, Canada; May 2011. (A two day visit.)
  • Waterloo Workshop in Computer Algebra 2011, W80, Wilfried Laurier University, Waterloo, Ontario, Canada; May 2011.
  • A talk at the Discrete Mathematics Seminar, Department of Mathematics, University of Wyoming, Laramie, Wyoming; July 2011 (a week visit).
  • Colloquium Speaker, Department of Mathematics, Howard University, Washington, DC; November, 2011.
  • Rocky Mountain Discrete Mathematics Day, University of Colorado at Fort Collins, Fort Collins, Colorado, May 2012; contributed talk.
  • Department of Mathematics, University of Wyoming, Laramie, Wyoming; May 2012 (a four day visit).
  • Department of Mathematics, UCSD, La Jolla, CA; August 2012 (a week visit.)
  • Midwestern Graph Theory (MIGHTY) LIII Conference, Iowa State University, Ames, Iowa, September 2012; contributed talk.
  • Alumni reunion/Pi Mu Epsilon induction ceremony, Saint Joseph’s University, April 2013; a fifty minute lecture.
  • The Twenty Fourth British International Conference on Combinatorics, Royal Holloway, University of London, July 2013, UK; contributed talk.
  • A talk at the Experimental Mathematics Seminar, Rutgers University, Piscataway, NJ; October 2013.
  • Colloquium Speaker, Department of Mathematical Sciences, Michigan Technological University, Houghton, Michigan;  October 2013 (a week visit).
  • AMS meeting, Special Section on Algebraic Methods in Graph Theory and Combinatorics, University of Tennessee, Knoxville, TN, March 2014  (session co-organizer).
  • An International Conference on Modern Trends in Algebraic Graph Theory,  Villanova University, Villanova, Pennsylvania, June 2014.
  • Workshop on Probabilistic and Extremal Combinatorics, Institute for Mathematics and its Applications, University of Minnesota in Minneapolis, MN, September 2014 (a week visit).
  • A talk at the Combinatorics Seminar, Department of Mathematics, Polytechnic University of Catalonia,  Barcelona, Spain, October 2014 (a two week visit).
  • A talk at the Combinatorics Seminar, Department of Mathematics, University of Warwick, UK; October 2014 (a week visit).
  • A talk at the Combinatorics Seminar, Department of Mathematics, University of Cambridge, UK; October 2014 (a week visit).
  • A talk at the Combinatorics Seminar, Department of Mathematics, UCSD, La Jolla, CA; March 2015 (a week visit).
  • The 12th International Conference on Finite Fields and Their Applications, Skidmore College, Saratoga, NY, July 2015; contributed talk.
  • Combinatorics: Challenges and Applications, Celebrating Noga Alon’s 60th Birthday, January, 2016, Tel Aviv University, Tel Aviv, Israel.
  • A talk at the Finite Fields and Combinatorics Seminar, Institute of Information Engineering of the Chinese Academy of Sciences, Beijing, China; June 2016 (a three day visit).
  • A talk at the Combinatorics Seminar, Department of Mathematics, Beijing University, China; July 2016 (a four day visit).
  • Department of Mathematics, Zhejiang University, Hongzhou, China; July 2016 (a three day visit).
  • Department of Mathematics, Tongji University, Shanghai, China; July 2016 (a five day visit).
  • Colloquium Speaker, Gettysburg College, Gettysburg, PA, April 2017.
  • Colloquium Speaker, University of South Florida, Tampa, FL, April 2017.
  • Colloquium and REU program Speaker, Lafayette College, Easton, PA, June 2017.
  • The Second Malta Conference in Graph Theory and Combinatorics, Qawra, Malta, June 2017; contributed talk.
  • A talk at the Discrete Mathematics Seminar, Virginia Commonwealth University, Richmond, VA, January, 2018.
  • A talk at the Discrete Mathematics Seminar, George Washington University, Washington, DC, April, 2018.
  • Building Bridges II. Conference to celebrate 70th birthday of Laszlo Lovasz. Budapest, Hungary, July 2018.
  • Co-organized (with S. Cioaba, B. Kronenthal, and T. Wong) a Special Section of the AMS meeting on Graph Theory and Applications, University of Delaware, Newark, Delaware, September 2018.
  • A talk at the Combinatorics Seminar, Iowa State University, Ames, Iowa, April 2019.
  • Conference dedicated to the 25th Anniversary of the Electronic Journal of Combinatorics, CanaDAM 2109, Simon Fraser University, Vancouver, Canada; May 2019.
  • Fq14: Conference on Finite Fields and their applications, Simon Fraser University, Vancouver, Canada; June 2019; contributed talk.
  • A talk at the Teaching Seminar, University of Delaware, May 2021.
  • A talk at the Mirka Miller’s Combinatorics Webinar Series, June 2021.
  • A talk at the Combinatorics Seminar, University of Wyoming, Laramie, WY, November 2021.
  • A talk at the Teaching Seminar, University of Delaware, November 2021.
  • A sequence of three talks:  In Elliptic World I, II, III,  University of  Delaware, December 2021, March 2022.
  • The 15th Annual Thomas L. Pirnot Lecture in Mathematics,  Kutztown University of Pennsylvania, April, 2022.
  • Six talks at the the Departments of Mathematics : SUSTech, Shenzhen; Yangzhou University, Yangzhou; HEU, Harbin: May-June 2024, China (one month visit).

Societies

  • American Mathematical Society (AMS)
  • Fellow of the Institute of Combinatorics and its Applications