\documentclass[12pt]{article} \usepackage{amsmath,mathrsfs,bbm} \usepackage{amssymb} \textwidth=4.825in \overfullrule=0pt \thispagestyle{empty} \begin{document} \noindent % % {\bf Juhani Nieminen, Matti Peltola and Pasi Ruotsalainen} % % \medskip \noindent % % {\bf Two Characterizations of Hypercubes} % % \vskip 5mm \noindent % % % % Two characterizations of hypercubes are given: 1)~A graph is a hypercube if and only if it is antipodal and bipartite $(0,2)$-graph. 2)~A graph is an $n$-hypercube if and only if there are $n$ pairs of prime convexes, the graph is a prime convex intersection graph, and each intersection of $n$ prime convexes (no one of which is from the same pair) is a vertex. \end{document} .