\magnification=1200
\hsize=4in
\overfullrule=0pt
\input amssym
%\def\frac#1 #2 {{#1\over #2}}
\def\emph#1{{\it #1}}
\def\em{\it}
\nopagenumbers
\noindent
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{\bf Torsten Sander}
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\noindent
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{\bf On Certain Eigenspaces of Cographs}
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\noindent
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For every cograph there exist bases of the eigenspaces for the
eigenvalues $0$ and $-1$ that consist only of vectors with entries
from $\{0, 1, -1\}$, a property also exhibited by other graph
classes. Moreover, the multiplicities of the eigenvalues $0$ and $-1$
of a cograph can be determined by counting certain vertices of the
associated cotree.


\bye

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