Simple connectedness of Fano log pairs with semi-log canonical singularities
نویسندگان
چکیده
منابع مشابه
Rational Connectedness of Log Q-fano Varieties
Let X be a log Q-Fano variety, i.e, there exists an effective Q-divisor D such that (X,D) is Kawamata log terminal (klt) and −(KX + D) is nef and big. By a result of Miyaoka-Mori [15], X is uniruled. The conjecture ([10], [16]) predicts that X is rationally connected. In this paper, apply the theory of weak (semi) positivity of (log) relative dualizing sheaves f∗(KX/Y + ∆) (which has been devel...
متن کاملLog Canonical Singularities and Complete Moduli of Stable Pairs
0.1. This paper consists of two parts. In the first part, assuming the log Minimal Model Program (which is currently only known to be true in dim ≤ 3), we construct the complete moduli of “stable pairs” (X,B) of projective schemes with divisors that generalize the moduli space of n-pointed stable curves Mg,n to arbitrary dimension. The construction itself is a direct generalization of that of [...
متن کامل0 Log - Canonical Forms and Log Canonical Singularities
For a normal subvariety V of C with a good C∗-action we give a simple characterization for when it has only log canonical, log terminal or rational singularities. Moreover we are able to give formulas for the plurigenera of isolated singular points of such varieties and of the logarithmic Kodaira dimension of V \{0}. For this purpose we introduce sheaves of m-canonical and L2,m-canonical forms ...
متن کاملThe Indices of Log Canonical Singularities
Let (P 2 X; ) be a three dimensional log canonical pair such that has only standard coe cients and P is a center of log canonical singularities for (X; ). Then we get an e ective bound of the indices of these pairs and actually determine all the possible indices. Furthermore, under certain assumptions including the log Minimal Model Program, an e ective bound is also obtained in dimension n 4.
متن کاملNon-vanishing Theorem for Log Canonical Pairs
We obtain a correct generalization of Shokurov’s nonvanishing theorem for log canonical pairs. It implies the base point free theorem for log canonical pairs. We also prove the rationality theorem for log canonical pairs. As a corollary, we obtain the cone theorem for log canonical pairs. We do not need Ambro’s theory of quasi-log varieties.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Mathematische Zeitschrift
سال: 2019
ISSN: 0025-5874,1432-1823
DOI: 10.1007/s00209-019-02347-0