design/tpl: Universal=>conjunctive, existential=>disjunctive classification

master
Mike Gerwitz 2021-05-11 13:00:08 -04:00
parent 2407af56e4
commit 5808afc8a2
2 changed files with 31 additions and 11 deletions

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@ -64,10 +64,22 @@ is equivalent to the proposition
\logand \tameparam{pool\_depth\_ft} < 8.
\end{equation*}
\index{classification!universal}
\begin{definition}[Universal Classification]\dfnlabel{classu}
A classification~$c$ by default performs conjunction on its match
expressions $M_0\ldots M_n$.
\goodbreak
\index{classification!conjunctive}
\begin{definition}[\logand-Classification]\dfnlabel{classu}
A conjunctive\footnote{%
Conjunctive and disjunctive classifications used to be referred to,
respectively,
as \emph{universal} and \emph{existential},
referring to fact that
$\forall\Set{a_0,\ldots a_n}(a) \equiv a_0\logand\ldots\logand a_n$,
and similarly for $\exists$.
This terminology has changed since all classifications are in fact
existential over their matches' index sets,
and so the terminology would otherwise lead to confusion.
}
classification~$c$ performs conjunction on its match expressions
$M_0\ldots M_n$.
\begin{alignat*}{2}
&\xml{<classify as="}&&c\xml{" desc="$\ldots$">} \\
@ -80,18 +92,26 @@ is equivalent to the proposition
\end{alignat*}
\end{definition}
\index{classification!existential}
\begin{definition}[Existential Classification]\dfnlabel{classe}
A classification~$c$ with the attribute \xpath{@any="true"} performs
disjunction on its match expressions $M_0\ldots M_n$.
\index{classification!disjunctive}
\begin{definition}[\logor-Classification]\dfnlabel{classe}
A disjunctive classification~$d$\footnote{%
It is notationally convenient that~$c$ is a common prefix for both
\underline{c}lassification \emph{and} \underline{c}onjunction,
and also that~$d$ happens to follow~$c$ \emph{and} be the prefix for
\underline{d}isjunction.
This notation will only be used where such a distinction is relevant,
and $c$~will otherwise refer generically to any type of
classification.}
with the attribute \xpath{@any="true"} performs disjunction on its match
expressions $M_0\ldots M_n$.
\begin{alignat*}{2}
&\xml{<classify as="} &&c\xml{" any="true" desc="$\ldots$">} \\
&\xml{<classify as="} &&d\xml{" any="true" desc="$\ldots$">} \\
&\quad M_0 \\
&\quad \vdots \\
&\quad M_n \\
&\texttt{</classify>}
&&\equiv c\in\Bool \\
&&\equiv d\in\Bool \\
& &&\equiv \exists\left( M_0 \logor \ldots \logor M_n \right).
\end{alignat*}
\end{definition}

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@ -199,7 +199,7 @@ We therefore have
\indexsym{()}{tuple}
\index{tuple (\ensuremath{()})}
\index{relation|see {function}}
And ordered pair $(x,y)$ is also called a \emph{$2$-tuple}.
An ordered pair $(x,y)$ is also called a \emph{$2$-tuple}.
Generally,
an \emph{$n$-tuple} is used to represent an $n$-ary function,
where by convention we have $(x)=x$.