[Haskell-beginners] Would you shed light on "undefined values" please?

[Arlen Cuss]

Howdy,

> I am not clear why "bottom" is an important concept. Would you explain please?

I've been getting into this myself lately. Here's what I've been reading:

http://en.wikibooks.org/wiki/Haskell/Denotational_semantics
http://blog.ezyang.com/2010/12/hussling-haskell-types-into-hasse-diagrams/

Let us know if you find anything else!

Arlen