Kodaira Dimension - General Type

General Type

A variety of general type V is one of maximal Kodaira dimension (Kodaira dimension equal to its dimension):

Equivalently, K is a big line bundle; equivalently, the n-canonical map is generically injective for n sufficiently large.

For example, a variety with ample canonical bundle is of general type.

In some sense varieties of general type are generic, hence the term (discrete invariants of varieties of general type vary in more dimensions, and moduli space of varieties of general type have more dimensions; this is made more precise for curves and surfaces). A smooth hypersurface of degree d in the n-dimensional projective space is of general type if and only if d is greater than n+1. In this sense most smooth hypersurfaces in the complex projective space are of general type.

Varieties of general type seem too complicated to classify explicitly, even for surfaces.

Siu (1998) proved invariance of plurigenera under deformations for varieties of general type.

Read more about this topic:  Kodaira Dimension

Famous quotes containing the words general and/or type:

    I suggested to them also the great desirability of a general knowledge on the Island of the English language. They are under an English speaking government and are a part of the territory of an English speaking nation.... While I appreciated the desirability of maintaining their grasp on the Spanish language, the beauty of that language and the richness of its literature, that as a practical matter for them it was quite necessary to have a good comprehension of English.
    Calvin Coolidge (1872–1933)

    I can barely conceive of a type of beauty in which there is no Melancholy.
    Charles Baudelaire (1821–1867)