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Paper

#### What Graphs are 2-Dot Product Graphs?

##### Fulltext (public)

arXiv:1511.05009.pdf

(Preprint), 137KB

##### Supplementary Material (public)

There is no public supplementary material available

##### Citation

Johnson, M., Paulusma, D., & van Leeuwen, E. J. (2015). What Graphs are 2-Dot Product Graphs? Retrieved from http://arxiv.org/abs/1511.05009.

Cite as: http://hdl.handle.net/11858/00-001M-0000-002C-5393-3

##### Abstract

Let $d \geq 1$ be an integer. From a set of $d$-dimensional vectors, we
obtain a $d$-dot product graph by letting each vector ${\bf a}^u$ correspond to
a vertex $u$ and by adding an edge between two vertices $u$ and $v$ if and only
if their dot product ${\bf a}^{u} \cdot {\bf a}^{v} \geq t$, for some fixed,
positive threshold~$t$. Dot product graphs can be used to model social
networks. Recognizing a $d$-dot product graph is known to be \NP-hard for all
fixed $d\geq 2$. To understand the position of $d$-dot product graphs in the
landscape of graph classes, we consider the case $d=2$, and investigate how
$2$-dot product graphs relate to a number of other known graph classes.