**International Conferences and Meetings abroad**

- 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,
**Lahore, Pakistan**
- Delivered an invited talk (Spectra and energy of graphs) in the 3rd International Conference on Pure and applied Mathematics, November 10-11, University of
**Sargodha**, **Pakistan**
- 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 26
^{th} 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, NUST,
**Islamabad,** **Pakistan**.
- 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 3
^{rd} 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 7
^{th} 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 22
^{nd} 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 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)

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