Talk:Rational mapping

Very well written article!
 * Thanks! But it is still horribly incomplete, and I no longer write much. Ryan Reich (talk) 22:59, 15 November 2008 (UTC)

The map curves are the wrong way round, and more links need to be made to the section entitled theorems.(92.232.91.38 (talk) 12:46, 6 June 2009 (UTC)).


 * I'm sorry, but this makes no sense to me. What section, and what "map curves"? Ryan Reich (talk) 15:16, 7 June 2009 (UTC)

Empty domain?
In the definition, is $$U$$ (the domain of $$f$$) assumed to be non-empty? - Saibod (talk) 10:19, 4 January 2017 (UTC)

Bad writing
The section Birational equivalence begins as follows:

"Two varieties are said to be birationally equivalent if there exists a birational map between them; this theorem states that birational equivalence of varieties is identical to isomorphism of their function fields as extensions of the base field."

But no mention has been made of any "theorem", so it is entirely unclear what the phrase "this theorem" refers to.

I hope someone knowledgeable about this subject can fix this.