From 66d013368bd62f567171d11b727c92ed835b7586 Mon Sep 17 00:00:00 2001 From: David VandeBunte Date: Tue, 20 Feb 2024 10:23:36 -0600 Subject: [PATCH] Modal logic fixups (#363) * truth-at-w.tex: Add missing w * truth-in-model.tex: Add missing "in" to "we are interested which" * schemas.tex: Add missing w --- content/normal-modal-logic/syntax-and-semantics/schemas.tex | 2 +- content/normal-modal-logic/syntax-and-semantics/truth-at-w.tex | 2 +- .../normal-modal-logic/syntax-and-semantics/truth-in-model.tex | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/content/normal-modal-logic/syntax-and-semantics/schemas.tex b/content/normal-modal-logic/syntax-and-semantics/schemas.tex index baec265f..805dab2f 100644 --- a/content/normal-modal-logic/syntax-and-semantics/schemas.tex +++ b/content/normal-modal-logic/syntax-and-semantics/schemas.tex @@ -50,7 +50,7 @@ W$ be arbitrary. To show that a conditional is true at a world we assume the antecedent is true to show that consequent is true as well. In this case, let $\mSat{M}{\Box(!A \lif !B)}[w]$ and - $\mSat{M}{\Box !A}[w]$. We need to show $\mSat{M}{\Box !B}$. So let + $\mSat{M}{\Box !A}[w]$. We need to show $\mSat{M}{\Box !B}[w]$. So let $w'$ be arbitrary such that $Rww'$. Then by the first assumption $\mSat{M}{!A \lif !B}[w']$ and by the second assumption $\mSat{M}{!A}[w']$. It follows that $\mSat{M}{!B}[w']$. Since $w'$ diff --git a/content/normal-modal-logic/syntax-and-semantics/truth-at-w.tex b/content/normal-modal-logic/syntax-and-semantics/truth-at-w.tex index d1e83916..7f83c91d 100644 --- a/content/normal-modal-logic/syntax-and-semantics/truth-at-w.tex +++ b/content/normal-modal-logic/syntax-and-semantics/truth-at-w.tex @@ -80,7 +80,7 @@ \begin{proof} \begin{enumerate} \item $\mSat{M}{\lnot\Diamond\lnot !A}[w]$ iff $\mSat/{M}{\Diamond\lnot - !A}$ by definition of $\mSat{M}{}[w]$. $\mSat{M}{\Diamond\lnot + !A}[w]$ by definition of $\mSat{M}{}[w]$. $\mSat{M}{\Diamond\lnot !A}[w]$ iff for some $w'$ with $Rww'$, $\mSat{M}{\lnot !A}[w']$. Hence, $\mSat/{M}{\Diamond\lnot !A}[w]$ iff for all $w'$ with $Rww'$, $\mSat/{M}{\lnot !A}[w']$. We also have diff --git a/content/normal-modal-logic/syntax-and-semantics/truth-in-model.tex b/content/normal-modal-logic/syntax-and-semantics/truth-in-model.tex index fcd3fd07..f93bdc4c 100644 --- a/content/normal-modal-logic/syntax-and-semantics/truth-in-model.tex +++ b/content/normal-modal-logic/syntax-and-semantics/truth-in-model.tex @@ -10,7 +10,7 @@ \olsection{Truth in a Model} -Sometimes we are interested which !!{formula}s are true at every world +Sometimes we are interested in which !!{formula}s are true at every world in a given model. Let's introduce a notation for this. \begin{defn}