3,142 reputation
1838
bio website mathematik.uni-mainz.de/…
location Mainz
age 27
visits member for 4 years, 11 months
seen yesterday

Post-doc at Johannes-Gutenberg Universität Mainz. Interested in many things, but especially arithmetic geometry.


Jan
19
answered there exists a hypersurface H ⊂ X such that X \ H is Stein and L is trivial over X \ H
Jan
15
reviewed Approve The Metrizability of Symmetric Products of Metric Spaces
Jan
14
revised Isotriviality: two definitions
deleted 1 character in body
Jan
14
answered Isotriviality: two definitions
Jan
7
comment Valuative criterion for properness of DM stacks
Dear @Ben Lim, English sources for the valuative criteria are Romagny's notes on models of curves (Section 4) perso.univ-rennes1.fr/matthieu.romagny/articles/… and Edidin's paper on the moduli of curves math.missouri.edu/~edidin/Papers/mfile.pdf . In Edidin's notes, p. 18 also contains an example due to Vistoli showing the necessity of passing to a cover of Spec $K$. For a proof of the valuative criterion, Edidin references the paper of Deligne-Mumford on the irreducibility of $M_g$; see [DM, Theorem 4.18-4.19].
Dec
29
comment sanity check about a morphism from a stack to its coarse moduli space
@TomGraber Thank you for your comment. I think User74230 meant to write "quasi-finite" instead of "etale". This makes me wonder: aren't all etale morphisms representable?
Dec
25
answered sanity check about a morphism from a stack to its coarse moduli space
Dec
21
comment An extension of group schemes admitting Neron models
On the other hand, the implications a implies b and a implies e of Thm 10.2.1 hold in general (as you probably already know). There might be a way to circumvent the compactification results and to prove that a group scheme not containing any copy of G_a or G_m is "bounded" directly (but I doubt it...).
Dec
21
comment An extension of group schemes admitting Neron models
If I'm not mistaken, the necessary "compactification" resuts used in Thm 10.2.1 are now known for not necessarily commutative group schemes by the work of Gabber. Try googling Gabber's compactification theorem to see if you get something useful.
Dec
21
reviewed Reject Refereeing a Paper
Dec
20
answered Is there a Riemann existence theorem for orbifolds?
Dec
19
revised Weil height of an Abelian Variety with everywhere (potentially) good reduction
deleted 1 character in body
Dec
18
revised Weil height of an Abelian Variety with everywhere (potentially) good reduction
added some tags
Dec
18
answered Weil height of an Abelian Variety with everywhere (potentially) good reduction
Dec
15
comment The cohomology of an $S_{3}$ cover of an elliptic curve ramified in one point
@jmc You can only have two points. The partitions of six which are possible are given by 2+2+2 and 3+3 a priori. You can't have 2+2+2, because then deg R = 2- 1 + 2-1 +2-1 = 3 is odd.
Nov
30
reviewed Approve Functions in “gaps” in Hardy hierarchy
Nov
25
comment Fermat's last theorem over larger fields
@Pablo I added some more details to my comment above.
Nov
25
comment Fermat's last theorem over larger fields
@René Yes, I was worried about that. HIT just gives you points of degree five in this case, but probably no Galois points. If you pass to the Galois closure of $f$ you will generate many Galois points, but these might not be abelian...
Nov
25
revised Fermat's last theorem over larger fields
added 289 characters in body
Nov
25
comment Fermat's last theorem over larger fields
@Pablo I guess you are then already aware of what I wrote in my "answer", and that it doesn't work in fact (or does it?).