Griffiths group

From HandWiki

In mathematics, more specifically in algebraic geometry, the Griffiths group of a projective complex manifold X measures the difference between homological equivalence and algebraic equivalence, which are two important equivalence relations of algebraic cycles. More precisely, it is defined as

[math]\displaystyle{ \operatorname{Griff}^k(X) := Z^k(X)_\mathrm{hom} / Z^k(X)_\mathrm{alg} }[/math]

where [math]\displaystyle{ Z^k(X) }[/math] denotes the group of algebraic cycles of some fixed codimension k and the subscripts indicate the groups that are homologically trivial, respectively algebraically equivalent to zero.[1]

This group was introduced by Phillip Griffiths who showed that for a general quintic in [math]\displaystyle{ \mathbf P^4 }[/math] (projective 4-space), the group [math]\displaystyle{ \operatorname{Griff}^2(X) }[/math] is not a torsion group.

Notes

  1. (Voisin 2003)

References