Timeline for Special elements of the Cremona group
Current License: CC BY-SA 4.0
3 events
| when toggle format | what | by | license | comment | |
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| Nov 27, 2019 at 17:29 | comment | added | user237522 | Thank you very much! Your answer is very helpful. Please, what if we further assume that $u(x,0) v(x,0) \neq 0$? You have mentioned that the monoid of birational endomorphisms is quite complicated, so I guess that this further assumption would not help. Perhaps further assuming the contrary, namely, that $u(x,0)=0$ or $v(x,0)=0$ may yield something interesting? In the 2 examples in my question $\mathbb{C}[u(x,0),v(x,0)]=\mathbb{C}[x]$. In your example, $\mathbb{C}[u(x,0),v(x,0)]=\mathbb{C}$. (The non-zero assumption is probably 'not solvable'). | |
| Nov 27, 2019 at 16:56 | vote | accept | user237522 | ||
| Nov 27, 2019 at 13:59 | history | answered | Jérémy Blanc | CC BY-SA 4.0 |