Birational invariant

Birational invariant

In algebraic geometry, a birational invariant is a quantity or object that is well-defined on a birational equivalence class of algebraic varieties. In other words, it depends only on the function field of the variety.

For example in the case of an algebraic surface, the Hodge numbers "h"0,1 and "h"0,2 of a non-singular projective complex surface are birational invariants. The Hodge number "h"1,1 is not, since the process of blowing up a point to a curve on the surface can augment it.

External links

* [http://nyjm.albany.edu:8000/PacJ/p/2002/204-1-12.pdf A birational invariant for algebraic group actions]


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Birational geometry — In mathematics, birational geometry is a part of the subject of algebraic geometry, that deals with the geometry of an algebraic variety that is dependent only on its function field. In the case of dimension two, the birational geometry of… …   Wikipedia

  • Geometric invariant theory — In mathematics Geometric invariant theory (or GIT) is a method for constructing quotients by group actions in algebraic geometry, used to construct moduli spaces. It was developed by David Mumford in 1965, using ideas from the paper… …   Wikipedia

  • Algebraic curve — In algebraic geometry, an algebraic curve is an algebraic variety of dimension one. The theory of these curves in general was quite fully developed in the nineteenth century, after many particular examples had been considered, starting with… …   Wikipedia

  • Geometric genus — In algebraic geometry, the geometric genus is a basic birational invariant p g of algebraic varieties, defined for non singular complex projective varieties (and more generally for complex manifolds) as the Hodge number h n ,0 (equal to h 0, n by …   Wikipedia

  • Algebraic surface — In mathematics, an algebraic surface is an algebraic variety of dimension two. In the case of geometry over the field of complex numbers, an algebraic surface is therefore of complex dimension two (as a complex manifold, when it is non singular)… …   Wikipedia

  • List of mathematics articles (B) — NOTOC B B spline B* algebra B* search algorithm B,C,K,W system BA model Ba space Babuška Lax Milgram theorem Baby Monster group Baby step giant step Babylonian mathematics Babylonian numerals Bach tensor Bach s algorithm Bachmann–Howard ordinal… …   Wikipedia

  • Néron–Severi group — In algebraic geometry, the Néron–Severi group of a variety is the group of divisors modulo algebraic equivalence; in other words it is the group of components of the Picard scheme of a variety. Its rank is called the Picard number. It is named… …   Wikipedia

  • Plücker formula — In mathematics, a Plücker formula is one of an extensive family of counting formulae, of a type first developed in the 1830s by Julius Plücker, that relate the extrinsic geometry of algebraic curves in projective space to intrinsic invariants… …   Wikipedia

  • Francesco Severi — Naissance 13 avril 1879 Arezzo (Italie) Décès 8 décembre 1961 Rome (Italie) …   Wikipédia en Français

  • Resolution of singularities — Strong desingularization of Observe that the resolution does not stop after the first blowing up, when the strict transform is smooth, but when it is simple normal crossings with the exceptional divisors. In algebraic geometry, the problem of… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”