Examples of nonsingular irreducible curves which give reducible singular points of \(red(H_{d,g})\) (Q1086636)

Denote by \(H_{d,g}\) the open subscheme of the Hilbert scheme Hilb\(({\mathbb{P}}^ 3)\) consisting of smooth irreducible curves of degree \(d\) and genus \(g.\) The purpose of this paper is to give methods to construct examples of curves whose Hilbert points lie on more than one irreducible component of \(H_{d,g}.\) The first example is of an arithmetically Buchsbaum curve that can be deformed to projectively Cohen-Macaulay curves in two different ways. - The second example is a curve that can be deformed into a projectively Cohen-Macaulay curve and into an arithmetically Buchsbaum curve. The author uses notations and results from his previous papers [Publ. Res. Inst. Math. Sci. 19, 493-518 (1983; Zbl 0541.14029) and 20, 793-837 (1984; Zbl 0574.14030)].