Yt. Siu et Sk. Yeung, DEFECTS FOR AMPLE DIVISORS OF ABELIAN-VARIETIES, SCHWARZ-LEMMA, AND HYPERBOLIC HYPERSURFACES OF LOW DEGREES, American journal of mathematics, 119(5), 1997, pp. 1139-1172
We prove that the defect vanishes for a holomorphic map f from the aff
ine complex line to an abelian variety A and for an ample divisor D in
A. The proof uses the translational invariance of the Zariski closure
of the k-jet space of the image of f and the theorem of Riemann Roch
to construct a nonidentically zero meromorphic k-jet differential whos
e pole divisor is dominated by a divisor equivalent to pD and which va
nishes along the k-jet space of D to order q with p/g smaller than a p
rescribed small positive number. Then estimates involving the theta fu
nction with divisor D and the logarithmic derivative lemma are used. W
e also prove a pointwise Schwarz lemma which gives the vanishing of th
e pullback, by a holomorphic map from the affine complex line to a com
pact complex manifold, of a holomorphic jet differential vanishing on
an ample divisor. This pointwise Schwarz lemma is a slight modificatio
n of a statement whose proof Green and Griffiths sketched in their alt
ernative treatment of Bloch's theorem on entire curves in abelian vari
eties. The log-pole case of the pointwise Schwarz lemma is also given.
We construct examples of hyperbolic hypersurface whose degree is only
16 times the square of its dimension.