“…For n = 3 it is irreducible for d ≤ 11, see [40] and reducible for d ≥ 78, see [69,Example 4.3], see also §2.3. The punctual Hilbert scheme for n ≥ 4 is reducible when d ≥ 8 and irreducible for d ≤ 7, see [99] and also [80,Proposition 2. While the Hilbert scheme of A 3 was investigated for many years, it seems that the Gorenstein locus in A 4 received less attention. It is however important for applications to secant varieties, see [18,20].…”