\magnification=1200
\hsize=4in
\nopagenumbers
\noindent
%
%
{\bf Alexandr Kostochka}
%
%
\medskip
\noindent
%
%
{\bf On a Theorem of Erd\H os, Rubin, and Taylor on
Choosability of Complete Bipartite Graphs}
%
%
\vskip 5mm
\noindent
%
%
%
%
Erd\H os, Rubin, and Taylor found a nice correspondence
between the minimum order of a complete bipartite graph that is not
$r$-choosable and the minimum number of edges
in an $r$-uniform hypergraph that is not $2$-colorable
(in the ordinary sense). In this note we use
their ideas to derive similar correspondences
for complete $k$-partite graphs and
complete $k$-uniform $k$-partite hypergraphs.

\bye

.
