Rational curves of degree 16 on a general heptic fourfold

According to a conjecture of H. Clemens, the dimension of the space of rational curves on a general projective hypersurface should equal the number predicted by a naive dimension count. In the case of a general hypersurface of degree 7 in P-5, the conjecture predicts that the only rational curves should be lines. This has been verified by Hana and Johnsen for rational curves of degree at most 15. Here we extend their results to show that no rational curves of degree 16 lie on a general heptic fourfold. (C) 2013 Elsevier B.V. All rights reserved.