Numerical characterization conjecture for polarized manifolds via sectional geometric and Δ-genera

Let (X,L)(X,\mathcal{L}) be a polarized manifold of dimension n3n\geq 3. For each integer ii with 2in12\leq i\leq n-1, let KXK_X denote the canonical divisor, let gi(X,L)g_i(X,\mathcal{L}) denote the iith sectional geometric genus, let Δi(X,L)\Delta_i(X,\mathcal{L}) denote the iith Δ\Delta-genus, and let Ln\mathcal{L}^n be the top self-intersection number of L\mathcal{L}. Numerical characterization conjecture. The following conditions are equivalent:

KX=(ni)L.K_X=-(n-i)\mathcal{L}. Δi(X,L)=1and2g1(X,L)2=(i1)Ln.\Delta_i(X,\mathcal{L})=1\quad\text{and}\quad 2g_1(X,\mathcal{L})-2=(i-1)\mathcal{L}^n. Δi(X,L)>0and2g1(X,L)2=(i1)Ln.\Delta_i(X,\mathcal{L})>0\quad\text{and}\quad 2g_1(X,\mathcal{L})-2=(i-1)\mathcal{L}^n. gi(X,L)=1and2g1(X,L)2=(i1)Ln.g_i(X,\mathcal{L})=1\quad\text{and}\quad 2g_1(X,\mathcal{L})-2=(i-1)\mathcal{L}^n. gi(X,L)>0and2g1(X,L)2=(i1)Ln.g_i(X,\mathcal{L})>0\quad\text{and}\quad 2g_1(X,\mathcal{L})-2=(i-1)\mathcal{L}^n.

The conjecture seeks a numerical characterization of polarized manifolds satisfying KX=(ni)LK_X=-(n-i)\mathcal{L}, extending Fujita's characterization of Del Pezzo manifolds. The source presents this as the main theme of the paper; its resolution status is not specified here.

Sources & referencesView supporting material

Primary source

Yoshiaki Fukuma, “A numerical characterization of polarized manifolds (X,L) with K_X=-(n-i)L by the ith sectional geometric genus and the ith Δ-genus”, arXiv:1005.4722 (2010).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.