We introduce and study a likely condition that implies the following form of
Clemens' conjecture in degrees d between 10 and 24: given a general quintic
threefold F in complex \IP^4, the Hilbert scheme of rational, smooth and
irreducible curves C of degree d on F is finite, nonempty, and reduced;
moreover, each C is embedded in F with balanced normal sheaf
\O(-1)\oplus\O(-1), and in \IP^4 with maximal rank.Comment: Plain Tex, This eleven page paper is a joint manuscript, produced in
connection with the first author's participation in the conference "Geometry
and Physics", Zlatograd, Bulgaria, August 28 - Sept.2, 1995." This version
contains a small change in Remark (3.3); the hope expressed there has been
refine