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prochet

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Name prochet
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comment Smooth map to the stack of G-bundles
very enlightening thank you!
1d
asked lift elements in affine singular variety.
2d
comment descent for formally smooth maps
In the infinitesimal lifting property, can we reduce to easier rings, such local henselian or local for example?
Jun
16
asked descent for formally smooth maps
Jun
14
comment Smooth map to the stack of G-bundles
In my case, $Bun_{B,r}$ corresponds to the open substack obtained by base change from the analog open substack $\Bun_{T,r}$ consisting of $T$-torsors E such that $H^{1}(X,E\times^{T}V)=0$ for any representation $V$ of $T$ which appear as subquotients of $Lie(U^{-})$ where $U^{-}$ is the opposite unipotent radical of $B$
Jun
13
comment Smooth map to the stack of G-bundles
I don't understand the purpose of the lemma 14.2.1 then, why restricting to an open subset if everything is already smooth with connected fibers?
Jun
12
asked Smooth map to the stack of G-bundles
Jun
12
comment differential of the characteristic polynomial
For example if $F=k((\pi))$ and $\mathcal{O}=k[[\pi]]$ do we have that for $n$ big enough an section $h\in\mathfrak{g}(X-x)$ such that: $d\chi_{\gamma}(h)=\pi^{-n}\mathcal{O}^{*}+Q(\pi^{-1})$ with $Q$ a polynomial of degree less than n-1?
Jun
12
comment differential of the characteristic polynomial
$k$ an algebraically closed field.
Jun
12
comment differential of the characteristic polynomial
the motivation is the following: Let $F$ a local field at a closed point $x$ of a smooth projective curve $X$ over $k$ (completion of function field at the place $x$). I take $\gamma\in G(F)$ regular semsisimple, we then have a map $d\chi_{\gamma}:\mathfrak{g}(F)\rightarrow \mathbb{A}^{r}(F)$ my question is to try to characterize the image of $d\chi_{\gamma}(\mathfrak{g}(X-x))$ where $\mathfrak{g}(X-x)$ denotes the section of $\mathfrak{g}$ with values in $X-x$.
Jun
11
asked differential of the characteristic polynomial
Jun
8
comment Galois cohomology of the field of Laurent series
or at least do we have that any $T$-torsor on $k((t))$ is trivial? As a matter of fact I think that $k((t))$ is of cohomological dimension one only if $k$ is algebraically closed.
Jun
8
asked Galois cohomology of the field of Laurent series
Jun
8
comment closed subscheme of ind scheme
yes, that's right.
Jun
8
comment closed subscheme of ind scheme
maybe we also need to assume that $X$ is a indscheme over a countable set.
Jun
8
asked closed subscheme of ind scheme
Jun
6
asked open immersion, affine grassmanian and negative loop group
May
29
asked etale cohomology of an abelian variety and its dual
May
25
asked open immersion between affine spaces
May
19
asked affine schubert cells and bruhat order
May
17
asked affine weyl group and affine schubert cells
May
14
comment weights and exceptional root systems
thanks a lot for your detailed answer.
May
13
comment weights and exceptional root systems
It doesn't always hold, because in case $D_{n}$ it never holds, but maybe there is sth that I don't understand in your answer?
May
13
asked weights and exceptional root systems
May
13
awarded  Supporter
May
10
comment solve the singularities of parabolic orbits of schubert cells
yes but a resolution of singularities of $\overline{BwP}$ is birational on $BwP$ and not on $PwP$ a priori
May
10
asked solve the singularities of parabolic orbits of schubert cells
May
7
comment quasi-minuscule representations
And for these representations, what is the characteristic polynomial? More generally where can we find the polynomial invariants for exceptional groups?
May
7
comment quasi-minuscule representations
yes but we don't know to which highest weight they correspond.
May
7
asked quasi-minuscule representations
May
6
comment group generated by Coxeter elements
How do we know that they generate a normal subgroup? And for $C_{2n+1}$ or $B_{2n+1}$ do we still obtain W?
May
5
asked group generated by Coxeter elements
Apr
16
comment The intersection complex and the Cohen-Macaulay property
d is the codimension, IC is the intersection complex.
Apr
15
comment The intersection complex and the Cohen-Macaulay property
Let assume also that both X and Y are equidimensionnal, and that a resolution of singularities for X gives by base change a resolution of singularities for Y.
Apr
15
asked The intersection complex and the Cohen-Macaulay property
Apr
14
asked on flat morphisms
Apr
13
asked on rational singularities
Apr
12
asked semicontinuity results for weights
Apr
6
comment sections of vector bundles transversal to a divisor
I mean that for a point $x\in X$ and $s$ a section of $E$, either $x\in S$ and the $s(x)\notin D$, either $x\in X-S$ and then s(x) needs to meet transversally $D$.
Apr
4
asked sections of vector bundles transversal to a divisor
Mar
20
asked on geometric Satake and functions
Feb
19
asked on degree zero elements in adelic groups
Feb
14
asked on z-extensions
Feb
13
comment sections of vector bundles
Yes I shouldn't have formulate like this. In fact, I only need the proposition for $V'\subset V$ two vector spaces such that $E$ (resp E') are the trivial vector bundles of fibres V and V'
Feb
13
asked sections of vector bundles
Feb
9
comment minuscule representations and classical groups
I stated for classical groups to make the statement easier, because although $E_{6}$ and $E_{7}$ have minuscule weights, $E_{8}$ $F_{4}$ and $G_{2}$ don't. Moreover, I know that groups don't have to be simply connected to have minuscule weights or coweights, because in my comment I took the example of $GL_{n}$. Nevertheless, if I take $SL_{n}$ for example, it doesn't have minuscule coweights, so my question was, is it possible to have a $z$-extension of $SL_{n}$, for example, that admits minuscule coweights.
Feb
8
comment on trivialisation of T-torsors
$x$ is a closed point on the curve
Feb
8
comment minuscule representations and classical groups
and in fact, my question is rather for minuscule coweights,
Feb
8
comment minuscule representations and classical groups
the comment is in two part, the example is to answer your second question. I used classical types, because we now that in each type, the simply connected group associated to it has at least one minuscule representations. For exceptional type, a group of type $G_{2}$ doesn't have minuscule representations.
Feb
8
comment minuscule representations and classical groups
I restrict for classical groups, because for exceptional types, there is not minuscule weights. For instance, if I take $PGL_{n}$ there is no minuscule irréducible representations, but for $GL_{n}$ yes