 Griffiths group

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

where formula_2 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.