## Contributions to Riemann-Roch on projective 3-folds with only canonical singularities and applications.(English)Zbl 0662.14026

Algebraic geometry, Proc. Summer Res. Inst., Brunswick/Maine 1985, part 1, Proc. Symp. Pure Math. 46, 221-231 (1987).
[For the entire collection see Zbl 0626.00011.]
A result of M. Reid [same proceedings, Proc. Symp. Pure Math. 46, 345-414 (1987; Zbl 0634.14003)] gives a formula for the plurigenera of a 3-fold X with canonical singularities in terms of the characteristic numbers of X and an explicit formula on an “equivalent basket” of cyclic quotient singularities.
Here the explicit formula is manipulated to a more convenient form, and it is shown that vanishing of plurigenera restricts the number and type of singularities in the basket. It is shown that if $$\chi$$ ($${\mathcal O}_ X)<0$$ then $$P_ 2\geq 4$$; if $$\chi$$ ($${\mathcal O}_ X)=0$$, $$P_ 2\geq 1$$ and $$P_ 4>2$$; and if $$\chi$$ ($${\mathcal O}_ X)=1$$ then $$P_{12}\geq 1$$ and $$P_{24}\geq 2$$. These results rest on extensive numerical computations.
Reviewer: C.T.C.Wall

### MSC:

 14J30 $$3$$-folds 14J17 Singularities of surfaces or higher-dimensional varieties 14C35 Applications of methods of algebraic $$K$$-theory in algebraic geometry 14B05 Singularities in algebraic geometry

### Citations:

Zbl 0626.00011; Zbl 0634.14003