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Higher dimensional examples of manifolds whose adjoint bundles are not spanned

Takeshi Kawachi

alg-geomarXiv:alg-geom/9603023

Abstract

Let (X,L) be an n-dimensional polarized variety. Fujita's conjecture says that if Ln>1 then the adjoint bundle KX+nL is spanned and KX+(n+1)L is very ample. There are some examples such that KX+nL is not spanned or KX+(n+1)L is not very ample. These are (¶n,Ø(1)), hypersurface M of degree 6 in weighted projective space ¶(3,2,1,1,·s ,1) with ØM(1) and numerically Godeaux surface etc. Numerically Godeaux surface is the quotient space of a Fermat type hypersurface of degree 5 in ¶3 by an action of order 5. These examples are not so much. We construct new examples for any dimention.

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