Zobrazeno 1 - 10
of 70
pro vyhledávání: '"Pirutka, Alena"'
Autor:
Cadoret, Anna, Pirutka, Alena
Assuming natural variational realization conjectures, we give uniform bounds for the obstruction to the integral Tate conjecture in 1-dimensional families of algebraic varieties over an infinite finitely generated field.
Comment: 15 pages
Comment: 15 pages
Externí odkaz:
http://arxiv.org/abs/2410.21010
Autor:
Pirutka, Alena, Zhang, Zhijia
Let X be a smooth projective rational variety carrying a regular action of a finite abelian group G. We give examples of effective computation of the Brauer group of the quotient stack [X/G] in dimensions 2 and 3 using residues in Galois cohomology a
Externí odkaz:
http://arxiv.org/abs/2410.05072
We consider the question whether a real threefold X fibred into quadric surfaces over the real projective line is stably rational (over R) if the topological space X(R) is connected. We give a counterexample. When all geometric fibres are irreducible
Externí odkaz:
http://arxiv.org/abs/2406.00463
Autor:
Pirutka, Alena
In this note we define a subgroup $H^i_{nr,\pi}$ of unramified cohomology group $H^i_{nr}$ of a fibration $\pi:X\to S$. This subgroup can be used efficiently in refined specialization arguments and allows to detect the failure of stable rationality o
Externí odkaz:
http://arxiv.org/abs/2312.00144
Autor:
Charles, François, Pirutka, Alena
Soit $X$ une vari\'et\'e projective et lisse, d\'efinie sur un corps de nombres. Sous l'hypoth\`ese $H^2(X,\mathcal O_X)=0,$ Colliot-Th\'el\`ene et Raskind ont d\'emontr\'e que le sous-groupe de torsion $CH^2(X)_{tors}$ du groupe de Chow en codimensi
Externí odkaz:
http://arxiv.org/abs/2207.05805
We investigate local-global principles for Galois cohomology, in the context of function fields of curves over semi-global fields. This extends work of Kato's on the case of function fields of curves over global fields.
Comment: 19 pages, to app
Comment: 19 pages, to app
Externí odkaz:
http://arxiv.org/abs/2001.05429
We study when kernels of inflation maps associated to extraspecial p-groups in stable group cohomology are generated by their degree two components. This turns out to be true if the prime is large enough compared to the rank of the elementary abelian
Externí odkaz:
http://arxiv.org/abs/1809.11023
Autor:
Cadoret, Anna, Pirutka, Alena
Let $F$ be a finitely generated regular field extension of transcendence degree $\geq 2$ over a perfect field $k$. We show that the multiplicative group $F^\times/k^\times$ endowed with the equivalence relation induced by algebraic dependence on $k$
Externí odkaz:
http://arxiv.org/abs/1808.04944
Publikováno v:
European Journal of Mathematics 4 (2018), no. 3, 732-760
We study the stable rationality problem for quadric and cubic surface bundles over surfaces from the point of view of the degeneration method for the Chow group of 0-cycles. Our main result is that a very general hypersurface X of bidegree (2,3) in P
Externí odkaz:
http://arxiv.org/abs/1710.07270
Publikováno v:
Ãpijournal de Géométrie Algébrique, Volume 2 (December 10, 2018) epiga:3950
En combinant une m\'ethode de C. Voisin avec la descente galoisienne sur le groupe de Chow en codimension $2$, nous montrons que le troisi\`eme groupe de cohomologie non ramifi\'ee d'un solide cubique lisse d\'efini sur le corps des fonctions d'une c
Externí odkaz:
http://arxiv.org/abs/1709.00597