X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=week1.mdwn;h=8484b17f975b74344e233ed94868b6e2a65c3b6e;hp=388fb9fcbbd47c5fb252c352c5c7e4ec4d5c6362;hb=6885a008cfcbb9fed72b19db62a6046665860c44;hpb=0df9a0974bf6e02aa9f5f63164f409d8b26da67a diff --git a/week1.mdwn b/week1.mdwn index 388fb9fc..8484b17f 100644 --- a/week1.mdwn +++ b/week1.mdwn @@ -62,13 +62,13 @@ Some authors reserve the term "term" for just variables and abstracts. We won't Examples of expressions:
-x -(y x) -(x x) -(\x y) -(\x x) -(\x (\y x)) -(x (\x x)) +x +(y x) +(x x) +(\x y) +(\x x) +(\x (\y x)) +(x (\x x)) ((\x (x x)) (\x (x x)))
@@ -76,7 +76,7 @@ The lambda calculus has an associated proof theory. For now, we can regard the proof theory as having just one rule, called the rule of **beta-reduction** or "beta-contraction". Suppose you have some expression of the form: - ((\a M) N) + ((lambda a M) N) that is, an application of an abstract to some other expression. This compound form is called a **redex**, meaning it's a "beta-reducible expression." `(\a M)` is called the **head** of the redex; `N` is called the **argument**, and `M` is called the **body**.