diff --git a/draft/draft.tex b/draft/draft.tex index e130c1c..ab68b8d 100644 --- a/draft/draft.tex +++ b/draft/draft.tex @@ -287,6 +287,15 @@ \newcommand{\gra}{\mathbf{Gra}} \newcommand{\obj}{\mathbf{Obj}} +\newcommand{\simeet}{% + \mathbin{% + \ooalign{% + $\sqcap$\cr + \hidewidth\raisebox{0.2ex}{\scalebox{0.44}{$\otimes$}}\hidewidth\cr + }% + }% +} + \newcommand{\bba}{ \mathrel{% @@ -1613,13 +1622,14 @@ Then we have \end{tikzcd} \end{equation*} We recall that in the above diagram $\sigma_3$ is a bisimulation, and the rest are simulations. - -We can also define $\join$ and $\meet$ on morphisms as follows: +\begin{definition}\label{def:join-meet} +We define $\join$ and $\meet$ on morphisms as follows: \begin{gather*} \forall x_1,x_2\in X,\\ \sigma_1 \join \sigma_2 (x_1,x_2)= \sigma_1(x_1,x_2) \cup \sigma_2(x_1,x_2),\\ \sigma_1 \meet \sigma_2 (x_1,x_2)= (\mathcal{P}p_1)^\dagger\comp\sigma_1(x_1,x_2) \cap (\mathcal{P}p_1)^\dagger\comp\sigma_2(x_1,x_2)\times(\mathcal{P}p_2)^\dagger\comp\sigma_1(x_1,x_2) \cap (\mathcal{P}p_2)^\dagger\comp\sigma_2(x_1,x_2). \end{gather*} +\end{definition} \begin{lemma}\label{lem:proj-dist-set} For relations $R_1$ and $R_2$ the following equation holds: \begin{gather*} @@ -1779,7 +1789,7 @@ We can also define $\join$ and $\meet$ on morphisms as follows: We have $\sigma(x_1,x_2)\in(\mathcal{P}R)^\dagger$, as $\alpha(x_1)\subseteq\mathcal{P}p_1(R)$ and $(\mathcal{P}p_2)^\dagger\comp\delta(x_1,x_2)\subseteq\mathcal{P}p_2(R)$ are inherited from $\delta$ being a simulation structure. Also, it obviously is a simulation as $(\mathcal{P}p_1)^\dagger\comp\sigma(x_1,x_2)=\alpha(x_1)$ and $(\mathcal{P}p_2)^\dagger\comp\sigma(x_1,x_2)\subseteq\alpha(x_2)$ as $(\mathcal{P}p_2)^\dagger\comp\delta(x_1,x_2)\subseteq\alpha(x_2)$. \end{proof} -\begin{prop} +\begin{prop}\label{prop:sym-rel-bisim} Assuming that $R$ is a symmetric relation, and $S\neq\emptyset$ is the set of all simulation structures of the type $R\to (\mathcal{P}R)^\dagger$, then the following morphism is the bisimulation structure: \begin{gather*} (\bigmeet_{\sigma\in S}\sigma)\join(\mathcal{P}s)^\dagger\comp(\bigmeet_{\sigma\in S}\sigma)\comp s @@ -1798,6 +1808,12 @@ We can also define $\join$ and $\meet$ on morphisms as follows: \end{gather*} By~\autoref{lem:alph-prod} there exists a simulation $\delta\in S$ for which we have $(\mathcal{P}p_1)^\dagger\comp\delta(x_1,x_2)=\alpha(x_1)$. So, $(\mathcal{P}p_1)^\dagger\comp(\bigmeet_{\sigma\in S}\sigma)(x_1,x_2)=\alpha(x_1)$. Then by the equations in~\eqref{eq:diag-sym-rel} we also get $(\mathcal{P}p_2)^\dagger\comp((\mathcal{P}s)^\dagger\comp(\bigmeet_{\sigma\in S}\sigma)\comp s)(x_1,x_2)=\alpha(x_2)$.\qed \end{proof} +\section{Symmetric Simulation in Quantaloids} +We generalize~\autoref{prop:sym-rel-bisim} in quantaloids. A quantaloid is a category enriched with suplattices. +Abstractly, first we define an operation that we need on morphisms that takes two simulation witnesses of type $R\to(FR)^\dagger$ to a morphism of type $R\to FX\times FX$: +\begin{gather*} + \sigma_1\simeet\sigma_2=(Fp_1)^\dagger\comp\sigma_1\meet(Fp_1)^\dagger\comp\sigma_2\times(Fp_2)^\dagger\comp\sigma_1\meet(Fp_2)^\dagger\comp\sigma_2 +\end{gather*} \section{Relators} We start the discussion with answering the question that why there can be multiple simulation structures based on~\autoref{def:sim}. At the moment we have limited the discussion to the category of sets and we are talking about the powerset functor. We know that $\sigma$ is unique in the following diagram: