Arithmetic genus

Arithmetic genus

In mathematics, the arithmetic genus of an algebraic variety is one of some possible generalizations of the genus of an algebraic curve or Riemann surface.

The arithmetic genus of a complex manifold of dimension "n" can be defined as a combination of Hodge numbers, namely

:"p""a" = "h""n",0 − "h""n" − 1, 0 + ... + (−1)"n"-1"h""1", 0.

When "n" = 1 we have χ = 1 − "g" where "g" is the usual (topological) meaning of genus of a surface, so the definitions are compatible.

By using "h""p","q" = "h""q","p" this can also be manipulated to a formula that is an Euler characteristic in coherent cohomology for the structure sheaf mathcal{O}_M:

: p_a=(-1)^n(chi(mathcal{O}_M)-1).,

This definition therefore can be applied to any locally ringed space.

ee also

* Geometric genus

References

*


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