Timeline for Is a section of a proper map proper?
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 8, 2011 at 1:53 | comment | added | Mariano Suárez-Álvarez | Right! ${}{}{}$ | |
| Oct 4, 2011 at 11:23 | vote | accept | Unknown | ||
| Oct 4, 2011 at 10:10 | comment | added | Georges Elencwajg | Dear Mariano, since 1971 schemes are no longer separated. In the original edition of EGA I, published by the IHES in 1960, schemes were indeed defined as separated preschemes. However a new edition of EGA I was published (by Springer) in 1971, in which the old "preschemes" were renamed "schemes" and the old "schemes" were renamed "separated schemes". So that since this date the word "scheme" implies no separation property. To my knowledge all books and articles published after 1971 have adopted the revised terminology, and consequently the word "prescheme" is no longer in use. | |
| Oct 4, 2011 at 4:13 | answer | added | Kevin Ventullo | timeline score: 7 | |
| Oct 4, 2011 at 3:06 | comment | added | Mariano Suárez-Álvarez | Schemes are separated... | |
| Oct 4, 2011 at 3:05 | comment | added | Unknown | Sure. But I'm interested in the general situation with no assumptions on X and Y. | |
| Oct 4, 2011 at 2:59 | comment | added | Mariano Suárez-Álvarez | The preimage under $s$ of a compact set $K\subseteq X$ is contained in $f(K)$, which is compact. If compact subsets of $X$ are closed, then the answer is then yes. | |
| Oct 4, 2011 at 2:48 | history | asked | Unknown | CC BY-SA 3.0 |