From 887b6de1d6b6b890cd4a1b1a24a61bf72244a0fe Mon Sep 17 00:00:00 2001 From: mark Date: Tue, 17 Oct 2023 11:45:33 -0700 Subject: [PATCH] Minor edits --- Advanced/Lambda Calculus/parts/00 intro.tex | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/Advanced/Lambda Calculus/parts/00 intro.tex b/Advanced/Lambda Calculus/parts/00 intro.tex index 9ce3324..97a1dcf 100755 --- a/Advanced/Lambda Calculus/parts/00 intro.tex +++ b/Advanced/Lambda Calculus/parts/00 intro.tex @@ -149,13 +149,18 @@ The first \say{pure} functions we'll define are $I$ and $M$: \end{itemize} Note that $I$ and $M$ don't have a meaning on their own. They are not formal functions. \par -Rather, it's notation that says \say{write $\lm x.x$ whenever you see $I$.} +Rather, they are abbreviations that say \say{write $\lm x.x$ whenever you see $I$.} \problem{} -Reduce the following expressions. +Reduce the following expressions. \par +\hint{ + Of course, your final result will be a function. \\ + Functions are the only objects we have! +} + \begin{itemize}[itemsep=2mm] \item $I~I$ \item $(I~I)~I$ @@ -167,7 +172,7 @@ Reduce the following expressions. \vfill In lambda calculus, functions are left-associative: \par -$(f~g~h)$ is equivalent to $((f~g)~h)$, not $(f~(g~h))$ +$(f~g~h)$ means $((f~g)~h)$, not $(f~(g~h))$ As usual, we use parentheses to group terms if we want to override this order: $(f~(g~h)) \neq ((f~g)~h)$ \par In this handout, all types of parentheses ( $(), [~],$ etc ) are equivalent. @@ -254,6 +259,7 @@ Evaluate $(C~a~b~x)$ for arbitary expressions $a$ and $b$. \par \problem{} Using the definition of $C$ above, evaluate $C~M~I~\star$ \par Then, evaluate $C~I~M~I$ \par +\note[Note]{$\star$ represents an arbitrary expression. Treat it like an unknown variable.} \vfill