Never ascribe to malice that which is adequately explained by incompetence
I am doing a startup!
Cross-browser testing from your browser!
I have written my fourth book!
Be faster than Larry Wall at command line!
You're viewing a comment by dasuxullebt and its responses.
The problem with the Y-Combinator is, that it cannot be typed. We have Y = \s.(\x.s(x x))(\x.s(x x)), such that Ys reduces to (\x.s(x x))(\x.s (x x)) which reduces to s((\x.s(x x))(\x.s(x x))) = s Ys, thus, having Ys reducing to all sssss...sYs, which means, Ys is not strongly normalizing - and since all typed lambda terms are strongly normalizing, it cannot be typed (actually, in the same way, no fixpoint combinator can be typed).
Anyway, even strongly typed programming languages like Haskell have recursion, even though mostly through calling the function by its name. In the theory of typed lambda terms, you therefore mostly axiomatically define recursion operators, like R:(a->a)->(a->bool)->a, which applies the first argument to a until (a->bool) gets true (there are a lot of other possibilities, though). Anyway, these cannot be expressed as terms, they must be defined axiomatically.
(why do I need your e-mail?)
It would be nice if you left your e-mail address. Sometimes I want to send a private message, or just thank for the great comment. Having your e-mail really helps.
I will never ever spam you.
(Your twitter name, if you have one. (I'm @pkrumins, btw.))
* use <pre>...</pre> to insert a plain code snippet.
* use <pre lang="lang">...</pre> to insert a syntax highlighted code snippet.
For example, <pre lang="python">...</pre> will insert Python highlighted code.
* use <code>...</code> to highlight a variable or a single shell command.
* use <a href="url" nospam>title</a> to insert links.
<a href="url" nospam>title</a>
* use other HTML tags, such as, <b>, <i>, <blockquote>, <sup>, <sub> for text formatting.
Type the word "coding_197": (just to make sure you're a human)
Please preview the comment before submitting to make sure it's OK.
Peteris Krumins' blog about programming, hacking, software reuse, software ideas, computer security, browserling, google and technology.
Reach me at:
Or meet me on:
Subscribe through an RSS feed:
(what is rss?)
Subscribe through email:
Enter your email address:
Delivered by FeedBurner
I love to read science books. They make my day and I get ideas for awesome blog posts, such as Busy Beaver, On Functors, Recursive Regular Expressions and many others.
Take a look at my Amazon wish list, if you're curious about what I have planned reading next, and want to surprise me. :)
See all top articles
See all downloads
See more detailed list of recent articles
See more detailed category information
See more detailed list of all articles