Skip to main content
3 events
when toggle format what by license comment
Mar 4, 2017 at 14:41 comment added Zach Teitler @UriBader: $\mathbb{P}^2$, $\mathbb{P}^2-\{P\}$, $\mathbb{A}^2$ are pairwise nonhomeomorphic because, as argued in the penultimate paragraph of [2], the latter two spaces contain disconnected (field other than $\mathbb{C}$!) irreducible curves while $\mathbb{P}^2$ does not; and $\mathbb{P}^2-\{P\}$ contains curves that meet every other curve (e.g., any curve not through $P$) while every curve in $\mathbb{A}^2$, say $f=0$, is disjoint from some other curve, such as $f=1$. I don't see how it helps for $\mathbb{A}^2-\{P\}$.
Mar 4, 2017 at 8:05 comment added Uri Bader Nice, Moishe. I assume it is also proved in [2] that $\mathbb{C}^2$ and $\mathbb{P}^2(\mathbb{C})-\text{point}$ are not homeomorphic. Could the method help deciding which one is hemoe to $\mathbb{C}^2-\text{point}$ (I cannot access the paper currently)?
Mar 4, 2017 at 1:28 history answered Moishe Kohan CC BY-SA 3.0