English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

Over a field of positive characteristic, a semisimple algebraic group $G$ mayhave some nonreduced parabolic subgroup $P$. In this paper, we study theSchubert and Bott-Samelson-Demazure-Hansen (BSDH) varieties of $G/P$, with $P$nonreduced, when the base field is perfect.  It is shown that in general the Schubert and BSDH varieties of such a $G/P$are not normal, and the projection of the BSDH variety onto the Schubertvariety has nonreduced fibers at closed points.  When the base field is finite, the generalized convolution morphisms betweenBSDH varieties are also studied. It is shown that the decomposition theoremholds for such morphisms, and the pushforward of intersection complexes by suchmorphisms are Frobenius semisimple.

Bott-Samelson-Demazure-Hansen Varieties for Projective Homogeneous Varieties with Nonreduced Stabilizers