منابع مشابه
0 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 کاملBoundedness of Fano Threefolds with Log-terminal Singularities of given Index
We prove that all Fano threefolds with log-terminal singularities of given index belong to finitely many families. This result was previously obtained by the author in the case of unipolar Fano varieties. [email protected]
متن کاملLog-terminal Singularities and Vanishing Theorems via Non-standard Tight Closure
Generalizing work of Smith and Hara, we give a new characterization of logterminal singularities for finitely generated algebras over C, in terms of purity properties of ultraproducts of characteristic p Frobenii. As a first application we obtain a Boutot-type theorem for log-terminal singularities: given a pure morphism Y → X between affine Q-Gorenstein varieties of finite type over C, if Y ha...
متن کاملGENERAL n-CANONICAL DIVISORS ON TWO-DIMENSIONAL SMOOTHABLE SEMI-LOG-TERMINAL SINGULARITIES
This paper is devoted to some fundumental calculation on 2-dimensional smoothable semi-log-terminal singularities. If we study minimal or canonical models of one parameter degeneration of algebraic surfaces, we must treat singularities that appear in the central fiber. Smoothable semi-log-terminal singularities are the singularities of the central fiber of the minimal model of degeneration, and...
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.
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ژورنال
عنوان ژورنال: Communications in Algebra
سال: 2017
ISSN: 0092-7872,1532-4125
DOI: 10.1080/00927872.2017.1404071