Enderton (logic). Add exercise 1.3 theorems and exercise prompts.
parent
f22712faf1
commit
9e9072ce45
|
@ -458,6 +458,32 @@
|
|||
TODO
|
||||
\end{proof}
|
||||
|
||||
\section{A Parsing Algorithm}%
|
||||
\hyperlabel{sec:parsing-algorithmm}
|
||||
|
||||
\subsection{\unverified{Lemma 13A}}%
|
||||
\hyperlabel{sub:lemma-13a}
|
||||
|
||||
\begin{lemma}[13A]
|
||||
Every wff has the same number of left as right parentheses.
|
||||
\end{lemma}
|
||||
|
||||
\begin{proof}
|
||||
Refer to \nameref{sub:balanced-parentheses}.
|
||||
\end{proof}
|
||||
|
||||
\subsection{\sorry{Lemma 13B}}%
|
||||
\hyperlabel{sub:lemma-13b}
|
||||
|
||||
\begin{lemma}[13B]
|
||||
Any proper initial segment of a wff contains an excess of left parentheses.
|
||||
Thus no proper initial segment of a wff can itself be a wff.
|
||||
\end{lemma}
|
||||
|
||||
\begin{proof}
|
||||
TODO
|
||||
\end{proof}
|
||||
|
||||
\section{Exercises 1}%
|
||||
\hyperlabel{sec:exercises-1}
|
||||
|
||||
|
@ -1930,4 +1956,91 @@
|
|||
|
||||
\end{proof}
|
||||
|
||||
\subsection{\sorry{Exercise 1.3.1}}%
|
||||
\hyperlabel{sub:exercise-1.3.1}
|
||||
|
||||
Rewrite the tautologies in the "selected list" at the end of Section 1.2, but
|
||||
using the conventions of the present section to minimize the number of
|
||||
parentheses.
|
||||
|
||||
\begin{answer}
|
||||
TODO
|
||||
\end{answer}
|
||||
|
||||
\subsection{\sorry{Exercise 1.3.2}}%
|
||||
\hyperlabel{sub:exercise-1.3.2}
|
||||
|
||||
Give an example of wffs $\alpha$ and $\beta$ and expressions $\gamma$ and
|
||||
$\delta$ such that $(\alpha \land \beta) = (\gamma \land \delta)$ but
|
||||
$\alpha \neq \gamma$.
|
||||
|
||||
\begin{answer}
|
||||
TODO
|
||||
\end{answer}
|
||||
|
||||
\subsection{\sorry{Exercise 1.3.3}}%
|
||||
\hyperlabel{sub:exercise-1.3.3}
|
||||
|
||||
Carry out the argument for \nameref{sub:lemma-13b} for the case of the
|
||||
operation $\mathcal{E}_{\neg}$.
|
||||
|
||||
\begin{answer}
|
||||
TODO
|
||||
\end{answer}
|
||||
|
||||
\subsection{\sorry{Exercise 1.3.4}}%
|
||||
\hyperlabel{sub:exercise-1.3.4}
|
||||
|
||||
Suppose that we modify our definition of wff by omitting all \textit{right}
|
||||
parentheses.
|
||||
Thus instead of
|
||||
$$((A \land (\neg B)) \Rightarrow (C \lor D))$$
|
||||
we use $$((A \land (\neg B \Rightarrow (C \land D.$$
|
||||
Show that we still have unique readability (i.e., each wff still has only one
|
||||
possible decomposition).
|
||||
\textit{Suggestion}: These expressions have the same number of parentheses as
|
||||
connective symbols.
|
||||
|
||||
\begin{answer}
|
||||
TODO
|
||||
\end{answer}
|
||||
|
||||
\subsection{\sorry{Exercise 1.3.5}}%
|
||||
\hyperlabel{sub:exercise-1.3.5}
|
||||
|
||||
The English language has a tendency to use two-part connectives: "both
|
||||
$\ldots$ and $\ldots$" "either $\ldots$ or $\ldots$" "if $\ldots$, then
|
||||
$\ldots$."
|
||||
How does this affect unique readability in English?
|
||||
|
||||
\begin{answer}
|
||||
TODO
|
||||
\end{answer}
|
||||
|
||||
\subsection{\sorry{Exercise 1.3.6}}%
|
||||
\hyperlabel{sub:exercise-1.3.6}
|
||||
|
||||
We have given an algorithm for analyzing a wff by constructing its tree from
|
||||
the top down.
|
||||
There are also ways of constructing the tree from the bottom up.
|
||||
This can be done by looking through the formula for innermost pairs of
|
||||
parentheses.
|
||||
Give a complete description of an algorithm of this sort.
|
||||
|
||||
\begin{answer}
|
||||
TODO
|
||||
\end{answer}
|
||||
|
||||
\subsection{\sorry{Exercise 1.3.7}}%
|
||||
\hyperlabel{sub:exercise-1.3.7}
|
||||
|
||||
Suppose that left and right parentheses are indistinguishable.
|
||||
Thus, instead of $\alpha \lor (\beta \land \gamma))$ we have
|
||||
$|\alpha \lor |\beta \land \gamma||$.
|
||||
Do formulas still have unique decomposition?
|
||||
|
||||
\begin{answer}
|
||||
TODO
|
||||
\end{answer}
|
||||
|
||||
\end{document}
|
||||
|
|
Loading…
Reference in New Issue