“…The rationality of UX Y D is studied already in our previous works; Lemma (3.1) and Example (3.5) of [20], O3 and O4 of [22], O5 of [17], and Proposition (1.5) of [16]. The following result uni®es various statements in [20,21].…”
Section: Hdivu Q Hdivrymentioning
confidence: 61%
“…Proof (cf. [7,16]). If a H`0 , then, as we have already seen, R is a klt singularity of index r with respect to K R DE by Theorem 2.6.…”
We give a description of a graded cyclic cover of a normal graded ring in terms of the Pinkham-Demazure description of normal graded rings R RX Y D. With the geometric description of ClR, it is shown that our cyclic cover S possesses the Pinkham-Demazure description S q RY YD [Theorem 1.3], by which we obtain a description of an index one cover [Corollary 1.7] of R. In O2, as an application of this description, we give criteria for the normal graded singularities to be Kawamata log terminal or to be log canonical. Further, in O3 we study the relations between cyclic covers of the Kummer type and cyclic covers obtained by using Veronese subrings. Our results extend S. Mori's structure theorem regarding graded factorial domains.
“…The rationality of UX Y D is studied already in our previous works; Lemma (3.1) and Example (3.5) of [20], O3 and O4 of [22], O5 of [17], and Proposition (1.5) of [16]. The following result uni®es various statements in [20,21].…”
Section: Hdivu Q Hdivrymentioning
confidence: 61%
“…Proof (cf. [7,16]). If a H`0 , then, as we have already seen, R is a klt singularity of index r with respect to K R DE by Theorem 2.6.…”
We give a description of a graded cyclic cover of a normal graded ring in terms of the Pinkham-Demazure description of normal graded rings R RX Y D. With the geometric description of ClR, it is shown that our cyclic cover S possesses the Pinkham-Demazure description S q RY YD [Theorem 1.3], by which we obtain a description of an index one cover [Corollary 1.7] of R. In O2, as an application of this description, we give criteria for the normal graded singularities to be Kawamata log terminal or to be log canonical. Further, in O3 we study the relations between cyclic covers of the Kummer type and cyclic covers obtained by using Veronese subrings. Our results extend S. Mori's structure theorem regarding graded factorial domains.
“…Moreover, we have the following result, proved by Tomari [23] (see also [26 There is a list of Sing(K ′ ) for 95 weight-vectors in [26]. The following are well-defined:…”
We give a result that relates the diffeomorphism type of the link of a nondegenerate semi-quasi-homogeneous hypersurface simple K3 singularity with the singularities of the normal K3 surface that appears as the exceptional divisor of the resolution of the singularity. As a result, we show that the links are diffeomorphic to the connected sum of copies of S 2 × S 3 . Moreover, we also show that the topological types of hypersurface simple K3 singularities defined by non-degenerate semi-quasihomogeneous polynomials are all different.
“…In fact, F is determined by the valuation corresponding to the exceptional divisor on the canonical model. We called this "the canonical filtration " [18]. Theorem (4.3.2)(cf.…”
Section: Special Cases: the Purely Elliptic Singularitiesmentioning
confidence: 99%
“…(4.10.2) X 6,18 ⊂ P (1,3,5,6,9) as the second Veronesian of X 36 ⊂ P (1,5,12,18). (4.10.3) X 8,24 ⊂ P (3,4,5,8,12) as the second Veronesian of X 48 ⊂ P (3,5,16,24).…”
We study the Newton boundaries of hypersurface singularities from the viewpoint of the theory of filtered blowing-ups. We can construct counter examples to Reid's conjecture in the d(≥ 3)-dimensional cases which is related to the problem about the existence of good embedding for the criterion about the rationality (or the non-rationality). For 3-dimensional case, our examples contains a simple K3 singularity which does not belong to the famous list consisting of 95 types.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.