design/tpl: \vdash=>\infer and index entry

master
Mike Gerwitz 2021-05-10 16:54:19 -04:00
parent 4e7b882aed
commit cb9ccfe5f3
2 changed files with 17 additions and 14 deletions

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@ -28,7 +28,9 @@ When you see any of these prefixed with ``0.'',
We reproduce here certain axioms and corollaries of propositional logic for
convenience and to clarify our interpretation of certain concepts.
The use of the symbols $\logand$, $\logor$, and~$\neg$ are standard.
The symbol $\vdash$ means ``infer''.
\indexsym\infer{infer}
\index{infer (\ensuremath\infer)}
The symbol $\infer$ means ``infer''.
We use $\implies$ in place of $\rightarrow$ for implication,
since the latter is used to denote the mapping of a domain to a codomain
in reference to functions.
@ -36,30 +38,30 @@ We further use $\equiv$ in place of $\leftrightarrow$ to represent material
equivalence.
\begin{definition}[Logical Conjunction]
$p,q \vdash (p\logand q)$.
$p,q \infer (p\logand q)$.
\end{definition}
\begin{definition}[Logical Disjunction]
$p \vdash (p\logor q)$ and $q \vdash (p\logor q)$.
$p \infer (p\logor q)$ and $q \infer (p\logor q)$.
\end{definition}
\begin{definition}[Law of Excluded Middle]
$\vdash (p \logor \neg p)$.
$\infer (p \logor \neg p)$.
\end{definition}
\begin{definition}[Law of Non-Contradiction]
$\vdash \neg(p \logand \neg p)$.
$\infer \neg(p \logand \neg p)$.
\end{definition}
\begin{definition}[De Morgan's Theorem]
$\neg(p \logand q) \vdash (\neg p \logor \neg q)$
and $\neg(p \logor q) \vdash (\neg p \logand \neg q)$.
$\neg(p \logand q) \infer (\neg p \logor \neg q)$
and $\neg(p \logor q) \infer (\neg p \logand \neg q)$.
\end{definition}
\indexsym\equiv{equivalence}
\index{equivalence!material (\ensuremath{\equiv})}
\begin{definition}[Material Equivalence]
$p\equiv q \vdash \big((p \logand q) \logor (\neg p \logand \neg q)\big)$.
$p\equiv q \infer \big((p \logand q) \logor (\neg p \logand \neg q)\big)$.
\end{definition}
$\equiv$ denotes a logical identity.
@ -67,11 +69,11 @@ Consequently,
it'll often be used as a definition operator.
\begin{definition}[Logical Implication]
$p\implies q \vdash (\neg p \logor q)$.
$p\implies q \infer (\neg p \logor q)$.
\end{definition}
\begin{definition}[Truth Values]\dfnlabel{truth-values}
$\vdash\true$ and $\vdash\neg\false$.
$\infer\true$ and $\infer\neg\false$.
\end{definition}
@ -115,8 +117,8 @@ $\forall$ denotes first-order universal quantification (``for all''),
\begin{remark}[Vacuous Truth]
By Definition~7, $\Exists{x\in\emptyset}P \equiv \false$
and by \dfnref{forall}, $\Forall{x\in\emptyset}P \equiv \true$.
And so we also have the tautologies $\vdash \neg\Exists{x\in\emptyset}P$
and $\vdash \Forall{x\in\emptyset}P$.
And so we also have the tautologies $\infer \neg\Exists{x\in\emptyset}P$
and $\infer \Forall{x\in\emptyset}P$.
\end{remark}
\begin{definition}[Boolean/Integer Equivalency]\dfnlabel{bool-int}
@ -156,7 +158,7 @@ We therefore have
\begin{align}
A \rightarrow B &\subset A\times B, \\
f : A \rightarrow B &\vdash f \subset A\times B, \\
f : A \rightarrow B &\infer f \subset A\times B, \\
f = \alpha \mapsto \alpha' : A \rightarrow B
&= \Set{(\alpha,\alpha')
\mid \alpha\in A \logand \alpha'\in B}, \\
@ -281,7 +283,7 @@ This defines a matrix to be more like a multidimensional array,
with no requirement that the lengths of the vectors be equal.
\begin{corollary}[Matrix Row Length Variance]\corlabel{matrix-row-len}
$\vdash \Exists{M\in\Matrices}{\neg\Forall*{j}{\Forall{k}{\len{M_j} = \len{M_k}}}}$.
$\infer \Exists{M\in\Matrices}{\neg\Forall*{j}{\Forall{k}{\len{M_j} = \len{M_k}}}}$.
\end{corollary}
\corref{matrix-row-len} can be read ``there exists some matrix~$M$ such that

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@ -77,6 +77,7 @@
\newcommand\Matrices{\ensuremath{\Vectors^{\Vectors^\Real}}}
\let\union\cup
\let\infer\vdash
\newcommand\len[1]{\ensuremath{\left|#1\right|}}