
Delivered an invited talk, in the 11th Conference on Graph Theory and Algebraic Combinatorics, March 45, 2021, Urmia University, Iran (Online)

Delivered an invited talk, in the 5th Combinatorics and Graph Theory Conference, November 78, 2020, Xiamen, China (Online)

Delivered an invited talk, in the International Workshop on Graph Theory Combinatorics and Applications, October 910, 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 24, 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 1519, 2019, University of Valencia, Valencia, Spain

Delivered an invited talk in the Lebanese International Conference in Mathematics and Applications, April 1518, 2019, Lebanese University of Beirut, Beirut, Lebanon

Delivered key note talks in 2nd Sharjah International Mathematics Spring School, March 2425, 2019, University of Sharjah, Sharjah, UAE

Delivered a contributed talk on Laplacian spectra of graphs and Brouwer's conjecture, in MIGHTY2018, September 2829, 2018, Purdue University, Fort Wayne, USA

Delivered a contributed talk on Signed graph coloring, in the International Workshop on Graph Labelling, September 2628, 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 19, 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 3031, 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, Lahore, Pakistan

Delivered an invited talk (Spectra and energy of graphs) in the 3rd International Conference on Pure and applied Mathematics, November 1011, University of Sargodha, Pakistan

Delivered a contributed talk in the 26th British Combinatorial Conference, July 37, 2017, University of Strathclyde, Glasgow, Scotland, UK

Delivered a contributed talk in the 15th Cologne Twente Workshop on Graphs and Combinatorial Optimization, June 68, 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 1619, 2017, Lebanese University of Beirut, Beirut, Lebanon

Visitng Professor to Xian JiotongLiverpool International University, Suzhou, Delivered an extension lecture on "Ëuler's formula on planar graph and its applications", November 13, 2016, China

Delivered an invited talk (Signless Laplacian eigenvalues of a graph) in the International Conference on Graph Theory, Combinatorics and Applications, October 2931, 2016, Zhejiang Normal University, Jinhua, China

Delivered an invited talk in Shanghai MiniWorkshop 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 1519, 2015, Djillai Liabes University, Sidi Bel Abbes, Algeria

Presented a contributed talk (Laplacian energy of graphs) in the 34th Colloquium on Combinatorics, November 67, 2015, Technishe Universitat Ilmenau, Ilmenau, Germany

Delivered an invited talk in the Lebanese International Conference on Mathematics and Applications, May 2629, 2015, Lebanese University of Beirut, Beirut, Lebanon

Visiting Professor to Faculty of Mathematics and Natural Sciences, Insitut Teknologi Bandung, November 0107, 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 1321, 2014, Seoul, South Korea

Participated in the 26^{th} International Conference on Formal Power Series and Algebraic Combinatorics, June 29July 03, 2014, Chicago, USA

Delivered a Planery talk (Energy of signed graphs and signed digraphs) in International Workshop on Discrete Structures, March 0507, 2014, NUST, Islamabad, Pakistan.

Presented a contributed talk (Strong double graphsenergy and Laplacian energy) in International Conference in Mathematical Technology of NetworksQGraphs , Dec. 0407, 2013, ZIF, University of Bielefeld, Bielefeld, Germany

Delivered an invited talk (Tournaments, oriented graphs and football sequences) I the 3^{rd} IndoTaiwanese Conference in Discrete Mathematics, November, 1922, 2013, Taipei, Taiwan

Delivered a contributed talk in the 12th Cologne Twente Workshop on Graphs and Combinatorial Optimization, May 2123, 2013, University of Twente, Enschede, Netherlands

Participated, Presented a contributed talk (Scores, Losing scores and degrees in hypertournaments) and Chaired a session in the ICTPIPM Workshop and Conference in Combinatorics and Graph Theory, Sept 0314, 2012, ICTP, Trieste, Italy

Delivered an invited lecture on Some Applications of Graph Theory in Istanbul Commerce University, Feb, 1315, 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. 912, 2012, Siofok, Hungary.

Presented a contributed talk (Mark sequences in bipartite multidigraphs) in International Congress of Industrial and Applied Mathematics, (ICIAM2011), July 1822, 2011,Vancouver, Canada

Presented a contributed talk (Clusterability of portfolio signed graphs) in International Conference on Games and Decision in Risk and Reliability, May 1921, 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 78, 2011, Penang, Malaysia

Presented a contributed talk (Applications of Graph Theory in Mathematics) in Conference Mathematics and Applications, March 2324, 2011, AlImam 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 28July 02, 2010, University Paris Sud, France

Presented a contributed talk (On imbalances in bipartite multidigraphs) in Algebraic Combinatorics and Applications, April 1118, 2010 University Bureuth, Germany

Visiting Professor, July 1922, 2009, Queenmary College, University of London, London, England

Presented a contributed talk (On rimbalances in tripartite rdigraphs) in the 7^{th} International Society of Analysis and Applications Congress (ISAAC), July 1318, 2009, Imperial College, London, England

Presented a contributed talk (On scores in multipartite hypertournaments) in the 22^{nd} British Combinatorial Conference (BCC), July 511, 2009, St. Andrews University, Scotland

Presented a contributed talk (Graph Theory and Applications) in the International Congress of Industrial and Applied Mathematics (ICIAM07), July 1620, 2007 ETH Zurich, Switzerland

Visiting Professor to Nanjing University, China, April 211, 2007, Nanjing, China

Visiting Professor to Eotvos Lorand University, Feb. 210, 2005, Budapest, Hungary

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 2025, 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 1921, 2019.

Delivered an Invited talk in the International Conference on Algebra and its Related fields and Applications, Aligarh Muslim University, Aligarh, December 1719, 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 1314, 2018 (Graphs and Applications).

Delivered an invited talk in International Conference on Theoretical Computer Science and Discrete Mathematics, December 35, 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 710, 2018, BITS, Pilani, Goa Campus, Goa

Delivered an invited talk in the Workshop Emerging Trends in Mathematics, March 2829, 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 2022, 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 1924, 2016, Aliah University, Kolkata (Graphs and matrices)

Delivered an invited talk in the International Conference on Current Trends in Graph Theory and Computations, September 1719, 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 1619, 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 46, 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 1820, 2015, University of Kashmir (jointly with Tata Institute of Fundamental Research, Mumbai)

Delivered an invited talk in the Workshop on Mathematical Biology, April 24, 2015, University of Kashmir, India

Delivered an invited talk in The International Conference on Algebra, Geometry, Analysis and their applications (ICAGAA14) , Nov 2729, 2014, JMI, New Delhi

Delivered an Invited talk in International Conference on Applied Mathematics and Theoretical Computer Science, Jan 2425, 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 1720, 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. 1719, 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 911, 2012, jointly organized by nCARDMATH Kalasalingam University, Krishankoil, India and Ball State University, USA (Scores, losing scores and total scores in hypertournaments)

Visiting Professor to nCARDMATH Kalasalingam University, Krishankoil, India, Jan 412, 2012

Invited speaker in International workshop on setvaluations, signed graphs and geometry(IWSSG), Sep 0207, 2011, Mananthavady, Kerala (Signed degree sequences in signed graphs)

Presented a contributed talk in JK Science Congress, July 2526, 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 1416, 2001, Anna University, Chennai (Construction of oriented graphs)