2,686 reputation
1725
bio website math.unibas.ch/~blanc
location Basel
age 33
visits member for 2 years, 7 months
seen Dec 16 at 7:10

I am working mostly in birational geometry, especially in studying Cremona groups.


Dec
9
comment A question od being algebraic stable for birational map
What kind of characterization are you looking for? You gave the definition. Equivalently, you can ask that $(f^k)^*=(f^*)^k$ for $k>0$, where $*$ means the action on $NS$. But the definition you give is much easier to check.
Nov
9
reviewed Approve Exploiting the Linearity of the Pullback
Nov
8
reviewed Approve Copositivity under tensor products
Oct
7
reviewed Approve Is there a formula for the number of labeled forests with $k$ components on $n$ vertices?
Oct
4
reviewed Approve Lyapunov stability of linear system
Oct
4
reviewed Approve Lyapunov stability, nonlinear system
Sep
25
answered Blowing up along birational equivalent subvarieties
Sep
2
reviewed Approve Hamiltonian Isotopy class of Lagrangian Submanifold
Sep
2
awarded  Enlightened
Sep
2
awarded  Nice Answer
Aug
24
comment Pseudo-automorphisms on Fano varieties
Thanks for the nice answer.
Aug
22
comment Pseudo-automorphisms on Fano varieties
Thanks everybody for your help.
Aug
22
accepted Pseudo-automorphisms on Fano varieties
Aug
22
comment Pseudo-automorphisms on Fano varieties
Yes, the degree of a birational map $\mathbb{P}^n\dashrightarrow \mathbb{P}^n$ is the degree of the polynomials (given without common factors), and is also the induced map on the Picard group. @JasonStarr, Could you explain more what you mean with Hartog's Theorem / S2 extension in this context? I google it and did not understand exactly what you meant.
Aug
21
asked Pseudo-automorphisms on Fano varieties
Aug
2
reviewed Approve Existence of a family of elliptic curves with large torsion subgroup
Jul
31
answered Is there an algorithm to write down the 27 lines of a cubic surface?
Jul
27
reviewed Approve Discriminant and Different
Jul
23
asked Factors of the polynomial $X^n-a$
Jul
21
reviewed Approve How to think about CM rings?