Transvectants des formes binaires et représentations des groupes binaires polyhedraux
Travaux de Coates et Wiles sur la conjecture de Birch et Swinnerton-Dyer
Travaux de Zink
The diverse Dieudonné theories have as their common goal the classification of formal groups and -divisible groups. The most recent theory is Zink’s theory of displays. A display over a ring R is a finitely generated projective module over the ring of Witt vectors, , equipped with additional structures. Zink has shown that using this notion, more concrete than those previously defined, one can obtain a good theory and prove an equivalence theorem in great generality. I will give an overview of...
Traverso’s Isogeny Conjecture for -Divisible Groups
Triangular Actions on C3.
Troesch complexes and extensions of strict polynomial functors
We develop a new approach of extension calculus in the category of strict polynomial functors, based on Troesch complexes. We obtain new short elementary proofs of numerous classical -computations as well as new results. In particular, we get a cohomological version of the “fundamental theorems” from classical invariant theory for for big enough (and we give a conjecture for smaller values of ). We also study the “twisting spectral sequence” converging to the extension groups between the...
Twisted action of the symmetric group on the cohomology of a flag manifold
Classes dual to Schubert cycles constitute a basis on the cohomology ring of the flag manifold F, self-adjoint up to indexation with respect to the intersection form. Here, we study the bilinear form (X,Y) :=〈X·Y, c(F)〉 where X,Y are cocycles, c(F) is the total Chern class of F and〈,〉 is the intersection form. This form is related to a twisted action of the symmetric group of the cohomology ring, and to the degenerate affine Hecke algebra. We give a distinguished basis for this form, which is a...
Twisted gamma filtration and algebras with orthogonal involution
For the Grothendieck group of a split simple linear algebraic group, the twisted γ-filtration provides a useful tool for constructing torsion elements in -rings of twisted flag varieties. In this paper, we construct a non-trivial torsion element in the γ-ring of a complete flag variety twisted by means of a PGO-torsor. This generalizes the construction in the HSpin case previously obtained by Zainoulline.
Twists of Central Simple Algebras and Endomorphism Algebras of Some Abelian Varieties.
Twists of Modular Forms and Endomorphisms of Abelian Varieties.
Two-dimensional formal groups: from isomorphism to isogeny.