International Conferences and Meetings abroad

  • Delivered an invited talk in the Workshop On Combinatorics and its Applications, September 10-11, 2024, Shahid Rajaee Teacher Training University, Iran (On Euler's formula for planar graphs and regular polyhedra) Online
  • Delivered an invited lecture in the Seminar, November 8, 2023, Kuwait University, Kuwait (Laplacian eigenvalues of graphs) (Online)
  • Delivered a contributed talk in the International Conference, Number Theory and Combinatorics in Duluth, July 31 to August 4, 2023, University of Minnesota Duluth, USA
  • Delivered invited talks in the Summer School on Spectral Graph Theory, Bangladesh University of Science and Technology, June 17-19, 2023, Dhaka, Bangladesh
  • Delivered an invited talk in the Workshop on Mathematical Chemistry, may 11, 2023, Shahid Rajaee Teacher Training University, Iran (Online) On Ashraf's conjecture on signless Laplacian eigenvalues of a graph
  • Delivered an invited talk in the International Conference on Graphs, Combinatorics and Optimization, Feb. 6-8, 2022, BITS Pilani Dubai Campus, UAE, On the eigenvalues of the distance Laplacian matrix of graphs (Online)
  • Delivered an invited talk, in Combinatorics Today, July 14, 2021, Institut Technologi Bandung, Indonesia  On Laplacian eigenvalues of graphs  (Online)
  • Delivered an invited talk, in the 11th Conference on Graph Theory and Algebraic Combinatorics, March 4-5, 2021, Urmia University, Iran (Online)
  • Delivered an invited talk, in the 5th Combinatorics and Graph Theory Conference, November 7-8, 2020, Xiamen, China (Online)
  • Delivered an invited talk, in the International Workshop on Graph Theory Combinatorics and Applications, October 9-10, 2019, United Arab Emirates University, Al Ain, UAE
  • Delivered an invited talk, On Laplacian spectra of graphs, in the International Conference on Mathematics and Informatics, September 2-4, 2019, Sapientia Hungarian University of Transylvania, Targu Mures, Romania
  • Delivered a contributed talk, On the bounds for energy of a graph, in the International Congress on Industrial and Applied Mathematics, July 15-19, 2019, University of Valencia, Valencia, Spain
  • Delivered an invited talk in the Lebanese International Conference in Mathematics and Applications, April 15-18, 2019, Lebanese University of Beirut, Beirut, Lebanon
  • Delivered key note talks in 2nd Sharjah International Mathematics Spring School, March 24-25, 2019, University of Sharjah, Sharjah, UAE
  • Delivered a contributed talk on Laplacian spectra of graphs and Brouwer's conjecture, in MIGHTY2018,  September 28-29, 2018, Purdue University, Fort Wayne, USA
  • Delivered a contributed talk on Signed graph coloring, in the International Workshop on Graph Labelling,  September 26-28, 2018, Ball State University, Muncie, USA
  • Delivered a contributed talk on Brouwer's conjecture on the Laplacian eigenvalues of a graph, in International Congress of Mathematicians, August 1-9, 2018, Rio de Janerio, Brazil
  • Delivered an invited talk on Recent developments on Brouwer's conjecture for the Laplacian eigenvalues of a graph, in the workshop on Linear Algebra and Applications, July 30-31, 2018, UFF, Niteroi, Rio de Janerio, Brazil
  • Delivered a plenary talk in the Symposium on Graphs and Analysis, November 13, 2017, COMSATS Institute of Information Technology; Delivered an invited talk (Spectra and energy of graphs) in the 3rd International Conference on Pure and applied Mathematics, November 10-11, 2017
  • Delivered a contributed talk in the 26th British Combinatorial Conference, July 3-7, 2017, University of Strathclyde, Glasgow, Scotland, UK
  • Delivered a contributed talk in the 15th Cologne Twente Workshop on Graphs and Combinatorial Optimization, June 6-8, 2017, University of Cologne, Cologne, Germany
  • Delivered an invited talk (Graph theory and its applications) in Umm Al Qurra University, May 21, 2017,  Makkah, Saudia Arabia
  • Delivered an invited talk in the Lebanese International Conference on Mathematics and Applications, May 16-19, 2017, Lebanese University of Beirut, Beirut, Lebanon
  • Visitng Professor to Xian Jiotong-Liverpool International University, Suzhou, Delivered an extension lecture on "Ëuler's formula on planar graph and its applications", November 1-3, 2016, China
  • Delivered an invited talk (Signless Laplacian eigenvalues of a graph) in the International Conference on Graph Theory, Combinatorics and Applications, October 29-31, 2016, Zhejiang Normal University, Jinhua, China
  • Delivered an invited talk in Shanghai Mini-Workshop on Graph Theory, October 28, 2016, Shanghai Centre for Mathematical Sciences. Fudan University, Shanghai, China
  • Delivered a plenary talk (Laplacian eigenvalues of a graph and Brouwer's conjecture) in the International Conference on Discrete Mathematics and Computer Science, November 15-19, 2015, Djillai Liabes University, Sidi Bel Abbes, Algeria 
  • Presented a contributed talk (Laplacian energy of graphs) in the 34th Colloquium on Combinatorics, November 6-7, 2015, Technishe Universitat Ilmenau, Ilmenau, Germany
  • Delivered an invited talk in the Lebanese International Conference on Mathematics and Applications, May 26-29, 2015, Lebanese University of Beirut, Beirut, Lebanon
  • Visiting Professor to Faculty of Mathematics and Natural Sciences, Insitut Teknologi Bandung, November  01-07, 2014, Indonesia, Delivered an invited talk in Bandung Workshop on Combinatorics and  Optimization BWCOP 2014
  • Presented a contributed talk  (Energy of graphs and Laplacian energy of graphs) in International Congress of Mathematicians (ICM), August 13-21, 2014, Seoul, South Korea
  • Participated in the 26th International Conference on Formal Power Series and Algebraic Combinatorics, June 29-July 03, 2014, Chicago, USA, Delivered a Planery talk (Energy of signed graphs and signed digraphs) in International Workshop on Discrete Structures, March 05-07, 2014, National University of Science and Technology.
  • Presented a contributed talk (Strong double graphs-energy and Laplacian energy) in International Conference in Mathematical Technology of Networks-QGraphs ,  Dec.  04-07, 2013, ZIF, University of Bielefeld, Bielefeld,  Germany
  • Delivered an invited talk (Tournaments, oriented graphs and football sequences) I the 3rd Indo-Taiwanese  Conference in Discrete Mathematics, November, 19-22, 2013, Taipei, Taiwan
  • Delivered a contributed talk in the 12th Cologne Twente Workshop on Graphs and Combinatorial Optimization, May 21-23, 2013, University of Twente, Enschede, Netherlands
  • Participated, Presented a contributed talk  (Scores, Losing scores and degrees in hypertournaments) and Chaired a session  in the ICTP-IPM  Workshop and Conference in Combinatorics and Graph Theory, Sept 03-14, 2012, ICTP, Trieste,   Italy
  • Delivered an invited lecture on Some Applications of Graph Theory in Istanbul  Commerce University, Feb, 13-15, 2012,  Istanbul, Turkey
  • Presented a contributed talk (Imbalances in (a,b,p,q)-bipartite tournaments) in  International Conference on Mathematics and Computer Science,  (MACS2012),  Feb. 9-12, 2012,  Siofok, Hungary.
  • Presented a contributed talk (Mark sequences in bipartite multidigraphs) in International Congress of Industrial and  Applied Mathematics, (ICIAM2011),  July  18-22, 2011,Vancouver,  Canada
  • Presented a contributed talk (Clusterability of portfolio signed graphs) in International Conference on Games and  Decision in Risk and Reliability, May 19-21,  2011 Belgirate,  Milan, Italy
  • Presented a contributed talk (Optimum allocation in multivariate two stage sampling: A geometric  programming approach) in International Conference on  Operations and Statistics, April 7-8, 2011,  Penang,   Malaysia
  • Presented a contributed talk (Applications of Graph Theory in Mathematics) in Conference Mathematics and  Applications, March 23-24, 2011, Al-Imam Mohammad bin Saud Islamic University,  Riyadh,  Saudi  Arabia
  • Presented a contributed talk  (Imbalance sequences and sets in multipartite  multidigraphs) in French Combinatorial  Conference(FCC10), June  28-July 02,  2010,  University Paris Sud, France
  • Presented a contributed talk (On imbalances in bipartite multidigraphs) in  Algebraic  Combinatorics and  Applications, April 11-18, 2010  University  Bureuth, Germany
  • Visiting Professor, July 19-22, 2009, Queenmary College, University of  London,  London, England
  • Presented a contributed talk (On r-imbalances in tripartite r-digraphs) in the 7th  International Society of  Analysis  and  Applications Congress (ISAAC), July  13-18,  2009,   Imperial College,  London,  England
  • Presented a contributed talk (On scores in multipartite hypertournaments) in the  22nd  British Combinatorial Conference   (BCC),  July 5-11, 2009,   St. Andrews   University,   Scotland
  • Presented a contributed talk (Graph Theory and Applications)  in the  International  Congress of Industrial and Applied Mathematics (ICIAM07), July 16-20, 2007 ETH   Zurich,  Switzerland 
  • Visiting  Professor to Nanjing University, China, April 2-11, 2007,  Nanjing, China
  • Visiting Professor to Eotvos Lorand University, Feb. 2-10, 2005,  Budapest, Hungary


Conferences and meetings in India

  • Delivered an Endowement lecture in the International Conference on Discrete Mathematics, June 7-10, 2024, Savitribai Phule Pune University (Euler's formula on planar graphs and regular polyhedra)
  • Delivered an invited talk (online) in the Conference on Graph Theory and Additive Combinatorics, May 3-5, 2024, IIIT Allahabad (On the eigenvalues of the distance Laplacian matrix of graphs)
  • Delivered an invited lecture (Online) in the Refresher Course, University of Jammu, Jammu, February 23, 2024 (An Introduction to Graph theory).
  • Delivered an invited lecture in the Workshop on Research Methodology, 27 December, 2023 HRDC University of Kashmir, Srinagar
  • Delivered an invited talk in the International Conference of Ramanujan Mathematical Society, December 22-24, 2023, IIT Guwahati, Guwahati (Ihara zeta function and Ramanujan graphs)
  • Delivered an invited talk in the National Workshop on the spectrum and energy of graphs, November 16, 2023, Saint Paul's College, Kalamassery, Kerala, On Laplacian spectrum and energy of graphs (Online)
  • Delivered lectures in the Two Weeks Advanced Instructional School (AIS) Workshop on Combinatorics and Graph Theory, May 1-13, 2023, University of Kashmir (jointly with National Centre for Mathematics) Matchings in graphs
  • Delivered an invited talk in the International Conference on Number Theory and Graph Theory, MIT Manipal, Mangaluru, 18-20, January, 2023 (On geometric-arithmetic matrix and energy of graphs).
  • Delivered an invited talk in the International Conference on Graphs, Networks and Combinatorics, Ramanujan College, New Delhi, 10-12 January, 2023 (On eigenvalues and energy of the Sombor matrix of graphs)
  • Delivered an invited talk in the International Conference of 88th Annual Indian Mathematical Society, Birla Institute of Technology, Ranchi, December 27-30, 2022 (Laplacian eigenvalues of graphs)
  • Delivered an invited lecture (Online) in the Refresher Course, University of Kashmir, Srinagar, December 16, 2022
  • Delivered an invited lecture in Department of Mathematics, South Asian University, New Delhi, November 16, 2022 (Fascinating Mathematics, Examples)
  • Delivered an invited talk in Two days National Conference on Analysis and Discrete Mathematics, JKIMS, Srinagar, JK, October 17-18, 2022 (On Laplacian spectra of graphs)
  • Delivered an invited talk in the Workshop on Mathematics and its Applications, South Campus, University of Kashmir, Anantnag, JK, September 22, 2022  (Fascinating Mathematics-a few examples)
  • Delivered an invited talk in the Internationl Conference on Mathematical Sciences and its applications, School of Mathematical Sciences and its applications, SRTM University Nanded July 28-30 (Ihara zeta function and Ramanujan graphs)
  • Delivered an invited talk in Dibrugarh University, Assam June 13,2022 (An Introduction to Graph Theory).
  • Delivered two invited lectures in One-Week Faculty Development Programme (FDP) on Mathematical Analysis organized by Department of Mathematics, Panjab University Chandigarh with UGC-MHRD, January 4-10, 2022 (A brief tour of Analysis via Graph Theory)
  • Delivered a lecture in the National Day of Mathematics, December 23, 2021, University of Kashmir (Ramanujan graphs and Ihara zeta function)
  • Delivered a Key Note talk in the National Day of Mathematics, December 22, 2021, GDC, Baramulla (Contributions of Ramanujan)
  • Delivered a Key Note talk in the National Day of Mathematics, December 22, 2021, Central University of Kashmir (Ramanujan graphs)
  • Delivered an invited talk in the Teacher's Enrichment Programme on Functional Analysis, jointly organized by National Centre for Mathematics, IIT Mumbai and University of Kashmir, December 5, 2021 (A brief tour of Analysis via Graph Theory).

  • Delivered an invited talk (Online) in the Refresher Course, Ramanujan College, University of Delhi, March 22, 2021.

  • Delivered an invited talk (Online) in the Orientation Course, University of Kashmir, Srinagar, March 23, 2021.

  • Delivered an invited talk (Online) in the International Conference on recent trends in Mathematics and its applications to graphs, networks and petrinets, JNU Delhi, July 20-25, 2020 (On Laplacian eigenvalues of a graph and some conjectures).

  • Delivered an Invited talk in the International Conference on Applicable Mathematics, Ramanujan College, University of Delhi, December 19-21, 2019.

  • Delivered an Invited talk in the International Conference on Algebra and its Related fields and Applications,  Aligarh Muslim University, Aligarh, December 17-19, 2019 (further developments on Brouwer’s conjecture).

  • Delivered an invited talk in the Conference on Applied Mathematics, University of Jammu, May 30, 2019 (Spectra of graphs and graph energy).

  • Delivered an invited talk in the Conference on Algebra and Analysis, GGM Science College, Cluster University Jammu, December 13-14, 2018 (Graphs and Applications).

  • Delivered an invited talk in International Conference on Theoretical Computer Science and Discrete Mathematics, December 3-5, 2018, SSN College of Engineering, Chennai (On Laplacian spectra of graphs).

  • Delivered an invited lecturer at Karnatak University, Dharwad, Karnataka, October 13, 2018

  • Delivered an invited talk on the sum of the Laplacian eigenvalues of a graph, in the International Conference on Discrete Mathematics and its Applications to Network Sciences, July 7-10, 2018, BITS, Pilani, Goa Campus, Goa

  • Delivered an invited talk in the Workshop Emerging Trends in Mathematics, March 28-29, 2018, South Campus, University of Kashmir (Introduction to Graphs and Applications).

  • Delived an invited talk in the International Conference on Analysis and its Applications, November 20-22, 2017, Department of Mathematics, Aligarh Muslim University, Aligarh (Laplacian eigenvalues of a graph and Brouwer's conjecture).

  • Delivered an invited lecture in the Department of Mathematics, Manonmaniam Sundaranar University, Trinelveli, Tamil Nadu, October 27, 2017 (Graphs and groups).

  • Delivered an invited talk in the National level Workshop on Graph Theory: Algebraic and Algorithmic Aspects, December 19-24, 2016, Aliah University, Kolkata (Graphs and matrices)

  • Delivered an invited talk in the International Conference on Current Trends in Graph Theory and Computations, September 17-19, 2016, South Asian University, New Delhi ( Sum of signless Laplacian eigenvalues of a graph)

  • Delivered an invited talk in The International Conference on Graph Theory and Applications, December 16-19, 2015, Amrita Vishwa Vidyapeetham, Coimbatore, Tamil Nadu (Sum of Laplacian eigenvalues of a graph and Brouwer's conjecture)

  • Delivered an invited talk in the International Conference on Mathematical Biology, Analysis and Applications, June 4-6, 2015, Department of Applied Mathematics, AMU, Aligarh, India

  • Delivered an invited talk in the Research Promotion Workshop on Introduction to Graphs and Geometric Algorithms, May 18-20, 2015, University of Kashmir (jointly with Tata Institute of Fundamental Research, Mumbai)

  • Delivered an invited talk in the Workshop on Mathematical Biology, April 2-4, 2015, University of Kashmir, India

  • Delivered an invited talk in The International Conference on Algebra, Geometry, Analysis and their applications (ICAGAA-14) , Nov 27-29, 2014, JMI, New Delhi

  • Delivered an Invited talk in International Conference on Applied Mathematics and Theoretical Computer Science, Jan 24-25, 2013, St. Xavier’s Catholic  College of  Engineering, Nagercoil, Tamil Nadu, India (Combinatorics of digraph sequences)

  •  Participated in the International Conference On recent trends in Discrete Mathematics, December 17-20, 2012, Tata Institute of  Fundamental Research, Mumbai

  • Delivered an invited talk in National Seminar on The role of Mathematics in developing the creative thinking,  October 6, 2012, SP College, Srinagar, India   (Applications of Combinatorics and Graph Theory)

  • Delivered an invited talk in National Seminar on Applications of Mathematics  to  Science and Technology,  Sept 29, 2012, Baba Ghulam Shah Badshah University,  Rajouri, India  (Applications of Graph Theory in Science and Technology)

  • Presented a contributed talk in JK Science Congress, Sept. 17-19, 2012,  University of Kashmir, Srinagar, India  (Football Sequences and oriented graphs)

  • Delivered an invited talk in National Workshop on Role of mathematics in Science, Engineering and Technology, March 26, 2012, National Institute of  Technology,  Srinagar, India  (Pythagrean Theorem: A for thousand years history)

  • Delivered an invited talk in National Conference Theoretical Computer  Science  and  Discrete Mathematics    (NCTCSDM), Jan 9-11, 2012, jointly  organized by n-CARDMATH  Kalasalingam University, Krishankoil,  India and Ball State  University,  USA    (Scores, losing scores and total scores in hypertournaments)

  • Visiting Professor to n-CARDMATH  Kalasalingam University, Krishankoil,  India,  Jan 4-12, 2012

  • Invited speaker in International workshop on set-valuations, signed graphs and  geometry(IWSSG), Sep 02-07, 2011, Mananthavady, Kerala   (Signed degree sequences in signed graphs)

  • Presented a contributed talk in JK Science Congress, July 25-26, 2006,  University of  Kashmir, Srinagar,  India  (Some problems on scores in oriented graphs)

  • Presented a contributed talk in National Conference on Graph Theory and Applications, March 14-16, 2001,  Anna University, Chennai  (Construction of oriented graphs)