%Introductory beamer presentation: quickbeamer2.tex \documentclass{beamer} \usetheme{Berkeley} \begin{document} \title[Complete-simple distributive lattices]{A construction of complete-simple\\ distributive lattices} \author[]{George~A. Menuhin} \institute{Computer Science Department\\ University of Winnebago\\ Winnebago, MN 53714} \date{March 15, 2006} \begin{frame} \titlepage \end{frame} \begin{frame} \frametitle{Outline} \tableofcontents[pausesections] \end{frame} \section{Introduction} \begin{frame} \frametitle{Introduction} In this note, we prove the following result: \begin{theorem} There exists an infinite complete distributive lattice~$K$ with only the two trivial complete congruence relations. \end{theorem} \end{frame} \section[Construction]{The $\Pi^{*}$ construction} \begin{frame} \frametitle{The $\Pi^{*}$ construction} The following construction is crucial in the proof of our Theorem: \begin{definition} Let $D_{i}$, for $i \in I$, be complete distributive lattices satisfying condition~\textup{(J)}. Their $\Pi^{*}$ product is defined as follows: \[ \Pi^{*} ( D_{i} \mid i \in I ) = \Pi ( D_{i}^{-} \mid i \in I ) + 1; \] that is, $\Pi^{*} ( D_{i} \mid i \in I )$ is $\Pi ( D_{i}^{-} \mid i \in I )$ with a new unit element. \end{definition} \end{frame} \begin{frame} \frametitle{Illustrating the construction} \centering\includegraphics{products} \end{frame} \begin{frame} \frametitle{Notation} If $i \in I$ and $d \in D_{i}^{-}$, then \[ \langle \ldots, 0, \ldots, d, \ldots, 0, \ldots \rangle \] is the element of $\Pi^{*} ( D_{i} \mid i \in I )$ whose $i$-th component is $d$ and all the other components are $0$. See also Ernest~T. Moynahan, 1957. \end{frame} \section[Second result]{The second result} \begin{frame} \frametitle{The second result} Next we verify the following result: \begin{theorem} Let $D_{i}$, $i \in I$, be complete distributive lattices satisfying condition~\textup{(J)}. Let $\Theta$ be a complete congruence relation on $\Pi^{*} ( D_{i} \mid i \in I )$. If there exist $i \in I$ and $d \in D_{i}$ with $d < 1_{i}$ such that, for all $d \leq c < 1_{i}$, \begin{equation*} \langle \ldots, d, \ldots, 0, \ldots \rangle \equiv \langle \ldots, c, \ldots, 0, \ldots \rangle \pmod{\Theta}, \end{equation*} then $\Theta = \iota$. \end{theorem} \end{frame} \section{Proof} \begin{frame} \frametitle{Starting the proof} Since \begin{equation*} \langle \ldots, d, \ldots, 0, \ldots \rangle \equiv \langle \ldots, c, \ldots, 0, \ldots \rangle \pmod{\Theta}, \end{equation*} and $\Theta$ is a complete congruence relation, it follows from condition~(J) that \begin{equation*} \langle \ldots, d, \ldots, 0, \ldots \rangle \equiv \bigvee ( \langle \ldots, c, \ldots, 0, \ldots \rangle \mid d \leq c < 1 ) \pmod{\Theta}. \end{equation*} \end{frame} \begin{frame} \frametitle{Completing the proof} Let $j \in I$, $j \neq i$, and let $a \in D_{j}^{-}$. Meeting both sides of the congruence with $\langle \ldots, a, \ldots, 0, \ldots \rangle$, we obtain that \begin{equation*} 0 = \langle \ldots, a, \ldots, 0, \ldots \rangle \pmod{\Theta}, \end{equation*} Using the completeness of $\Theta$ and the penultimate equation, we get: \[ 0 \equiv \bigvee ( \langle \ldots, a, \ldots, 0, \ldots \rangle \mid a \in D_{j}^{-} ) = 1 \pmod{\Theta}, \] hence $\Theta = \iota$. \end{frame} \section{References} \begin{frame} \frametitle{References} \begin{thebibliography}{9} \bibitem{sF90} Soo-Key Foo, \emph{Lattice Constructions}, Ph.D. thesis, University of Winnebago, Winnebago, MN, December, 1990. \bibitem{gM68} George~A. Menuhin, \emph{Universal Algebra}, D.~van Nostrand, Princeton, 1968. \bibitem{eM57} Ernest~T. Moynahan, \emph{On a problem of M. Stone}, Acta Math. Acad. Sci. Hungar. \textbf{8} (1957), 455--460. \bibitem{eM57a} Ernest~T. Moynahan, \emph{Ideals and congruence relations in lattices.} II, Magyar Tud. Akad. Mat. Fiz. Oszt. K\"{o}zl. \textbf{9} (1957), 417--434. \end{thebibliography} \end{frame} \end{document}