English

Labels of real projective varieties

Algebraic Geometry 2019-09-26 v1

Abstract

Let XX be a complex projective variety defined over R\mathbb R. Recently, Bernardi and the first author introduced the notion of admissible rank with respect to XX. This rank takes into account only decompositions that are stable under complex conjugation. Such a decomposition carries a label, i.e., a pair of integers recording the cardinality of its totally real part. We study basic properties of admissible ranks for varieties, along with special examples of curves; for instance, for rational normal curves admissible and complex ranks coincide. Along the way, we introduce the scheme theoretic version of admissible rank. Finally, analogously to the situation of real ranks, we analyze typical labels, i.e., those arising as labels of a full-dimensional Euclidean open set. We highlight similarities and differences with typical ranks.

Keywords

Cite

@article{arxiv.1909.11170,
  title  = {Labels of real projective varieties},
  author = {Edoardo Ballico and Emanuele Ventura},
  journal= {arXiv preprint arXiv:1909.11170},
  year   = {2019}
}

Comments

18 pp

R2 v1 2026-06-23T11:24:50.160Z