Some remarks on rigid sheaves, helices and exceptional vector bundles on   Fano varieties over arbitrary fields
  In this paper we study the connection between rigid sheaves and separable-exceptional objects on Fano varieties over arbitrary fields. We give criteria for a rigid vector bundle on a Fano variety to be the direct sum of separable-exceptional bundles and for a separable-exceptional vector bundle to be part of a full separable-exceptional collection. 
Sa\v{s}a Novakovi\'c
math.AG