Tohoku Mathematical Journal
2011

December
SECOND SERIES VOL. 63, NO. 4

Tohoku Math. J.
63 (2011), 629-649

Title ON NEF AND SEMISTABLE HERMITIAN LATTICES, AND THEIR BEHAVIOUR UNDER TENSOR PRODUCT

Author Yves André

(Received March 11, 2010, revised August 11, 2010)
Abstract. We study the behaviour of semistability under tensor product in various settings: vector bundles, euclidean and hermitian lattices (alias Humbert forms or Arakelov bundles), multifiltered vector spaces.
  One approach to show that semistable vector bundles in characteristic zero are preserved by tensor product is based on the notion of nef vector bundles. We revisit this approach and show how far it can be transferred to hermitian lattices. J.-B. Bost conjectured that semistable hermitian lattices are preserved by tensor product. Using properties of {nef} hermitian lattices, we establish an inequality in that direction.
  We axiomatize our method in the general context of monoidal categories, and then give an elementary proof of the fact that semistable multifiltered vector spaces (which play a role in diophantine approximation) are preserved by tensor product.


2000 Mathematics Subject Classification. Primary 11E39; Secondary 14G25, 14H60.

To the top of this page

Back to the Contents