Talk:Y combinator: Difference between revisions

== Is this really the "Y" combinator? ==

According to [[wp:Fixed point combinator]], and [http://ttic.uchicago.edu/~pl/classes/CMSC336-Winter08/lectures/lec4.pdf here] page 6, and [http://ttic.uchicago.edu/~pl/classes/CMSC336-Winter08/lectures/lec4.pdf here] page 2, the Y combinator is the precise form <code>λf·(λx·f (x x)) (λx·f (x x))</code>, which does not work for applicative-order evaluation. The version you are using for Python is closely related to what they call the ''Z'' combinator, which is <code>λf. (λx. f (λy. x x y)) (λx. f (λy. x x y))</code> (the version you are using is just one step "before" this; one step of evaluation will produce this). So I am not sure if we should have named the article the "Y" combinator. --[[Special:Contributions/71.106.173.110|71.106.173.110]] 20:49, 1 March 2009 (UTC)