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Feb
1
comment Definition of ind-schemes
OK, I wrote down the details for myself... you're right. Sorry.
Feb
1
comment Definition of ind-schemes
@Martin: I don't think so. In fact, if you restrict to quasi-compact schemes and coverings formed by finite (flat, jointly surjective etc.) families then the inductive limit presheaf is a sheaf. Therefore the map from the presheaf to the sheaf is an isomorphism when evaluated on qc schemes. It is not really a question of glueing things and covering the intersections with affines etc.
Feb
1
comment Definition of ind-schemes
The equality $\text{Hom}(Y,\varinjlim X_n)=\varinjlim \text{Hom}(Y,X_n)$ extends quite easily from affine schemes $Y$ to quasi-compact ones. Away from qc schemes, I do not think it works.
Jan
31
answered A technical question about affine grassmanian
Jan
31
comment A technical question about affine grassmanian
You're welcome!
Jan
30
comment A technical question about affine grassmanian
I think you can find more details in Martin Kreidl's thesis, available at uni-due.de/~hx0051/Dissertation.pdf. Best,
Jan
26
awarded  Necromancer
Jan
24
awarded  Revival
Jan
24
comment Flat cohomology for finite infinitesimal group scheme over a perfect field
"some more argument seems to be needed to explain why $X^{perf}$ is a $G^{perf}$-torsor" : perfectization commutes with products, so if the map $G\times X \to X\times X$ is an isomorphism then $G^{perf}\times X^{perf} \to X^{perf}\times X^{perf}$ also.
Jan
24
answered Flat cohomology for finite infinitesimal group scheme over a perfect field
Jan
3
comment Nisnevich topology on non-(locally) Noetherian schemes
"the guy who asked", or "the girl who asked". After all, MO is for female mathematicians also.
Jan
2
revised Descent of functions along finite birational morphisms
added 306 characters in body
Jan
1
revised Pushing-forward morphisms
added 5 characters in body
Dec
31
revised Pushing-forward morphisms
added 16 characters in body
Dec
31
revised Pushing-forward morphisms
I realized the claim is not true in general. I provide explanations, a counter-example and examples where the claim still holds.
Dec
25
comment Is the realtive dualizing sheaf Cohen-Macaulay?
I seemed to remember that CM-ification is problematic in general: which existence result(s) do you have in mind (if any) ?
Dec
4
answered Completion of a local ring of a curve
Dec
4
revised Pushing-forward morphisms
added 5 characters in body
Dec
3
answered Pushing-forward morphisms
Nov
16
comment Open affine subscheme of affine scheme which is not principal
I agree it is not clear why $D(X,Y)$ is not principal. Also the role of $U$ and $V$ is not clear: can you take $U=V=1$ ?