This commit is contained in:
parent
c4da7b6c43
commit
a3f036ff8d
|
@ -6,8 +6,16 @@
|
|||
\newcommand{\Image}{\definitionLink{image}{monotone}}
|
||||
\let\imageNoLink\image
|
||||
\renewcommand{\image}[1]{\imageNoLink{#1}}
|
||||
\let\lubNoLink\lub
|
||||
\renewcommand{\lub}{\definitionLink{lubglb}{\lubNoLink}}
|
||||
\let\glbNoLink\glb
|
||||
\renewcommand{\glb}{\definitionLink{lubglb}{\glbNoLink}}
|
||||
\newcommand{\CompleteLattice}{\definitionLink{completelattice}{complete lattice}}
|
||||
|
||||
\let\topNoLink\top
|
||||
\renewcommand{\top}{\definitionLink{topbot}{\topNoLink}}
|
||||
\let\botNoLink\bot
|
||||
\renewcommand{\bot}{\definitionLink{topbot}{\botNoLink}}
|
||||
|
||||
\let\fixpointsOfNoLink\fixpointsOf{}
|
||||
\renewcommand{\fixpointsOf}{\definitionLink{fixpointsOf}{\fixpointsOfNoLink}}
|
||||
|
|
|
@ -3,4 +3,6 @@
|
|||
\newcommand{\lte}{\preceq}
|
||||
\newcommand{\image}[1]{[#1]}
|
||||
\newcommand{\define}{\coloneqq}
|
||||
\newcommand{\union}{\cup}
|
||||
\newcommand{\union}{\cup}
|
||||
\newcommand{\glb}{\bigwedge}
|
||||
\newcommand{\lub}{\bigvee}
|
||||
|
|
68
note.tex
68
note.tex
|
@ -15,6 +15,9 @@
|
|||
\pagestyle{plain}
|
||||
|
||||
\newtheorem{theorem}{Theorem}
|
||||
\newtheorem{corollary}{Corollary}
|
||||
\newtheorem{lemma}{Lemma}
|
||||
\newtheorem{proposition}{Proposition}
|
||||
|
||||
\begin{document}
|
||||
|
||||
|
@ -22,6 +25,8 @@
|
|||
|
||||
\definition{monotone}{define monotone}
|
||||
\definition{image}{define set image}
|
||||
\definition{lubglb}{define glb and lub}
|
||||
\definition{topbot}{define $\top$ and $\bot$}
|
||||
\definition{completelattice}{define complete lattice}
|
||||
|
||||
Hello world\cite{tarskilatticetheoretical1955}
|
||||
|
@ -30,31 +35,76 @@ First, we generalize Knaster-Tarski Fixpoint Theorem.
|
|||
$$\fixpointsOf(S)$$
|
||||
|
||||
|
||||
\begin{theorem}[Tarski-Knaster Fixpoint Theorem~\cite{tarskilatticetheoretical1955}]
|
||||
\begin{theorem}[Tarski-Knaster Fixpoint Theorem~\cite{tarskilatticetheoretical1955}]\label{tarskitheorem}
|
||||
For a \Monotone function $o$ over a \CompleteLattice $\langle \L, \lte \rangle$, we have that $\langle \fixpointsOf(o), \lte \rangle$ is a \CompleteLattice.
|
||||
\end{theorem}
|
||||
|
||||
\begin{theorem}
|
||||
Trivial attempt using set preimage / image to attain LUB / GLB in image lattice does not work.
|
||||
|
||||
Consider antichain of 2 that map to a chain in image.
|
||||
The antichain's LUB does maps to a third, distinct element which extends the chain to three in the image
|
||||
|
||||
If we attain LUB of preimage, then its not the least element :)
|
||||
\end{theorem}
|
||||
|
||||
\begin{theorem}\label{imagelattice}
|
||||
For a \Monotone function $o$ over a \CompleteLattice $\langle \L, \lte \rangle$, we have that $\langle o\imageNoLink{\L}, \lte \rangle$ is a \CompleteLattice.
|
||||
\end{theorem}
|
||||
\begin{proof}
|
||||
Consider $\langle \L', \lte' \rangle$ where
|
||||
Consider $\langle \L', \lte \rangle$ where
|
||||
\begin{align*}
|
||||
\L' \define \{ x' ~|~ x \in \L \} \\
|
||||
x' \lte' y' \iff x \lte y \textrm{ where } x, y \in \L
|
||||
x' \lte y' \iff x \lte y \textrm{ where } x, y \in \L
|
||||
\end{align*}
|
||||
Clearly, $\langle \L', \lte' \rangle$ is a \CompleteLattice.
|
||||
Combining $\L$ and $\L'$
|
||||
Combining $\L$ and $\L'$, we formulate $\L^*$:
|
||||
\begin{align*}
|
||||
\L^* \define \{ \top^*, \bot^* \} \union \L \union \L' \\
|
||||
\forall x^*, y^* \in \L^*, x^* \lte y^* \iff \begin{cases}
|
||||
(x^* = \bot^*) \lor (y^* = \top^*) \\
|
||||
two \\
|
||||
three
|
||||
\L^* &\define \{ \top^*, \bot^* \} \union \L \union \L' \\
|
||||
\forall x^*, y^* \in \L^*, x^* \lte y^* &\iff \begin{cases}
|
||||
(x^* = \bot^*) \lor (y^* = \top^*), \\
|
||||
\textrm{or } x, y \in \L, \\
|
||||
\textrm{or } x', y' \in \L'
|
||||
\end{cases}
|
||||
\end{align*}
|
||||
It is easy to show that $\langle \L^*, \lte \rangle$ is a \CompleteLattice.
|
||||
Consider the operator $o^*$ that maps elements from $\L$ to $\L'$ and every element in $\L'$ to itself.
|
||||
\begin{align*}
|
||||
o^*(x) \define \begin{cases}
|
||||
o(x)' & \textrm{if } x \in \L \\
|
||||
x & \textrm{otherwise}
|
||||
\end{cases}
|
||||
\end{align*}
|
||||
We have $o^*\image{\L \union \L'} \subseteq L'$ and $\fixpointsOf(o^*) = o\image{\L}' \union \{ \bot^*, \top^* \}$.
|
||||
By Tarski-Knaster Fixpoint Theorem (Theorem \ref{tarskitheorem}), $\fixpointsOf(o^*)$ is a \CompleteLattice.
|
||||
Thus, $o\image{\L} \union \{ \bot^*, \top^* \}$ is a \CompleteLattice. For any $S \subseteq \L$, we have $\glb S \not\in \{ \bot^*, \top^* \}$ and $\lub S \not\in \{ \bot^*, \top^* \}$, thus $\langle o\image{\L}, \preceq \rangle$ is a \CompleteLattice.
|
||||
\end{proof}
|
||||
|
||||
The following follows directly from the contrapositive of Theorem \ref{imagelattice}.
|
||||
\begin{corollary}
|
||||
If $\langle o\image{\L}, \lte \rangle$ is not a \CompleteLattice, then $o$ is not \Monotone.
|
||||
\end{corollary}
|
||||
|
||||
|
||||
\begin{definition}
|
||||
An approximator set $H$ captures a nondeterministic approximator $o$ if for each consistent pair $(x, y)$
|
||||
\begin{align*}
|
||||
(H\image{(x, y)}_1, H\image{(x, y)}_2) = o(x, y)
|
||||
\end{align*}
|
||||
\end{definition}
|
||||
|
||||
\begin{theorem}
|
||||
A nondeterministic approximator $o$ has a set of
|
||||
\end{theorem}
|
||||
|
||||
\begin{theorem}
|
||||
For any nondeterministic approximator $o$, there exists an approximator set $H$ s.t.\ gamma stable models correspond to n-stable models
|
||||
\end{theorem}
|
||||
\begin{proof}
|
||||
foo
|
||||
\end{proof}
|
||||
|
||||
|
||||
\bibliographystyle{plain}
|
||||
\bibliography{references}
|
||||
|
||||
|
|
Loading…
Reference in New Issue