Re: [Haskell-cafe] Lambda Calculus: Bound and Free formal definitions

On Wed, Dec 29, 2010 at 9:22 PM, Mark Spezzano <mark.spezzano@chariot.net.au

wrote:

Duh, Sorry. Yes, there was a typo

the second one should read

If E is a combination E1 E2 then X is bound in E if and only if X is bound in E1 or is bound in E2.

Seems odd. I recommend you always work from at least three different texts. Here's Hindley and Seldin<http://www.amazon.com/Lambda-Calculus-Combinators-Introduction-Roger-Hindley/dp/0521898854/ref=dp_ob_title_bk> : "An occurrence of a variable x in a term P is called - *bound* if it is in the scope of a \x in P (NB: using \ as lambda) - *bound and binding* iff it is the x in \x - *free* otherwise" The tricky question is: bound to what, exactly? -Gregg