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- Ayan Nandy, Sagnik Sen, Éric Sopena
- Journal of Graph Theory
- 2016

The clique number of an undirected graphG is the maximum order of a complete subgraph of G and is a well-known lower bound for the chromatic number ofG. Every proper k-coloring of G may be viewed as a homomorphism (an edge-preserving vertex mapping) of G to the complete graph of order k. By considering homomorphisms of oriented graphs (digraphs without… (More)

- Sujoy Kumar Bhore, Dibyayan Chakraborty, Sandip Das, Sagnik Sen
- CALDAM
- 2015

We define and study a class of graphs, called 2-stab interval graphs (2SIG), with boxicity 2 which properly contains the class of interval graphs. A 2SIG is an axesparallel rectangle intersection graph where the rectangles have unit height (that is, length of the side parallel to Y -axis) and intersects either of the two fixed lines, parallel to the X-axis,… (More)

- Pascal Ochem, Alexandre Pinlou, Sagnik Sen
- ArXiv
- 2014

Signed graphs are studied since the middle of the last century. Recently, the notion of homomorphism of signed graphs has been introduced since this notion captures a number of well known conjectures which can be reformulated using the definitions of signed homomorphism. In this paper, we introduce and study the properties of some target graphs for signed… (More)

- Sagnik Sen
- IWOCA
- 2012

- Reza Naserasr, Sagnik Sen, Qiang Sun
- Graphs and Combinatorics
- 2016

- Sagnik Sen
- Electronic Notes in Discrete Mathematics
- 2011

In this paper, we improve the existing bounds [2] for 2-dipath and oriented L(2, 1) span for the class of planar graphs with girth 5, 11, 16, cactus, wheels and leaf independent Halin graphs. Some of these bounds are tight.

- Sudarshan Kumar Khokhar, Neelima Aron, Sagnik Sen, Ganesh Pillay, Esha Agarwal
- Journal of cataract and refractive surgery
- 2017

PURPOSE
To compare the outcomes of torsional phacoemulsification with a new balanced tip (Intrepid) and a conventional tip (Kelman) using a single active-fluidics torsional phacoemulsification machine (Centurion).
SETTING
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
DESIGN
Prospective… (More)

- Julien Bensmail, Christopher Duffy, Sagnik Sen
- Graphs and Combinatorics
- 2017

- Reza Naserasr, Sagnik Sen, Qiang Sun
- ArXiv
- 2015

As an extension of the Four-Color Theorem it is conjectured that every planar graph of odd-girth at least 2k + 1 admits a homomorphism to PC2k = (Z 2 , {e1, e2, · · · , e2k, J}) where ei’s are standard basis and J is all 1 vector. Noting that PC2k itself is of odd-girth 2k + 1, in this work we show that if the conjecture is true, then PC2k is an optimal… (More)

- Sagnik Sen, Sagnik Sen
- 2013

In this paper we determine, or give lower and upper bounds on, the 2-dipath and oriented L(2, 1)-span of the family of planar graphs, planar graphs with girth 5, 11, 16, partial k-trees, outerplanar graphs and cacti.