\magnification=1200 \hsize=4in \overfullrule=0pt \input amssym \nopagenumbers \noindent % % {\bf Bo\v{s}tjan Bre\v{s}ar} % % \medskip \noindent % % {\bf Vizing-like Conjecture for the Upper Domination of Cartesian Products of Graphs -- The Proof} % % \vskip 5mm \noindent % % % % In this note we prove the following conjecture of Nowakowski and Rall: For arbitrary graphs $G$ and $H$ the upper domination number of the Cartesian product $G \,\square \, H$ is at least the product of their upper domination numbers, in symbols: $\Gamma(G \,\square \, H)\ge \Gamma(G)\Gamma(H).$ \bye .