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In this paper, we give a characterization of Fano type varieties of plc pairs. This extends a result due to Choi and Park for pklt pairs. Moreover, we show that for a plc pair $(X,\Delta)$, if no plc centers are contained in the augmented base locus $\mathbf{B}_{+}(-(K_X+\Delta))$, then $(X,\Delta)$ admits a good $-(K_X+\Delta)$-minimal model.

For Fano fibrations with $\epsilon$-lc singularities of a fixed dimension, we show the existence of bounded relative-global complements. If the base of the fibration is of dimension one, we even show the existence of bounded relative-global klt complements., Comment: 15 pages

In this paper, we initiate the study of a triple $(X,\Delta,D)$ which consists of a pair $(X,\Delta)$ and a polarizing pseudoeffective divisor $D$. The adjoint asymptotic multiplier ideal sheaf $\mathcal{J}(X,\Delta;\lVert D \rVert)$ associated to the triple gives a simultaneous generalization of the multiplier ideal sheaf $\mathcal{J}(D)$ and asymptotic multiplier ideal sheaf $\mathcal{J}(\lVert D \rVert)$. We describe the closed set defined by the ideal sheaf $\mathcal{J}(X,\Delta;\lVert D \rVert)$ in terms of the minimal model program. We also characterize the case where $\mathcal{J}(X,\Delta;\lVert D \rVert)=\mathcal{O}_X$. Lastly, we also prove a Nadel type vanishing theorem of cohomology using $\mathcal{J}(X,\Delta;\lVert D \rVert)$.

In this paper, we define potential log canonical threshold and prove that the set of those thresholds satisfies the ascending chain condition (ACC). We also consider collections of sequences of Fano type varieties and we study their basic properties including boundedness.

The purpose of this paper is to establish a subadditivity theorem of Okounkov bodies for algebraic fiber spaces. As applications, we obtain a product formula of the restricted canonical volumes for algebraic fiber spaces and a sufficient condition for an algebraic fiber space to be birationally isotrivial in terms of Okounkov bodies when a general fiber is of general type. Furthermore, we also prove the subadditivity of the numerical Iitaka dimensions for algebraic fiber spaces, and this confirms some numerical variants of the Iitaka conjecture. We hope that our results would provide a new approach toward the Iitaka conjecture.

To seek for the useful numerical analogues to the Iitaka dimension, various numerical Iitaka dimensions have been defined from a number of different perspectives. It has been accepted that all the known numerical Iitaka dimensions coincide with each other until the recent discovery of a counterexample constructed by Lesieutre. In this paper, we prove that many of them still coincide with the numerical Iitaka dimension introduced by Boucksom-Demailly-P\u{a}un-Peternell. On the other hand, we show that some other numerical Iitaka dimensions introduced by Nakayama and Lehmann can be arbitrarily larger than the rest of numerical Iitaka dimensions. We also study some properties of abundant divisors., Comment: 22 pages, comments welcome

We discuss some variants of cone theorem for movable curves in any codimensions., Comment: 16pages, 1 figure

We continue to explore the numerical nature of the Okounkov bodies focusing on the local behaviors near given points. More precisely, we show that the set of Okounkov bodies of a pseudoeffective divisor with respect to admissible flags centered at a fixed point determines the local numerical equivalence class of divisors which is defined in terms of refined divisorial Zariski decompositions. Our results extend Ro\'{e}'s work on surfaces to higher dimensional varieties although our proof is essentially different in nature., Comment: 20 pages

We generalize Kawamata's product formula for volumes of canonical divisors to arbitrary divisors using Okounkov bodies, Comment: 13 pages. Final version

The aim of this paper is to study the Okounkov bodies associated to abundant divisors. As a main result, we prove that the valuative Okounkov bodies of an abundant divisor encode all the numerical properties. We apply this result to recover the asymptotic base loci of an abundant divisor from the valuative Okounkov bodies. We also give a criterion of when the valuative and limiting Okounkov bodies of an abundant divisor coincide by comparing their Euclidean volumes. To obtain these results, we prove some variants of Fujita's approximations for Okounkov bodies using Iitaka fibrations., Comment: 28 pages, comments welcome, we have clarified the issue on numerical Iitaka dimensions

We first prove some basic properties of Okounkov bodies, and give a characterization of Nakayama and positive volume subvarieties of a pseudoeffective divisor in terms of Okounkov bodies. Next, we show that each valuative and limiting Okounkov bodies of a pseudoeffective divisor which admits the birational good Zariski decomposition is a rational polytope with respect to some admissible flag. This is an extension of the result of Anderson-K\"{u}ronya-Lozovanu about the rational polyhedrality of Okounkov bodies of big divisors with finitely generated section rings., Comment: 14 pages, deleted previous Section 5 and fixed several gaps in the previous version. to appear in Taiwanese J. Math. (special issue for the proceedings of the conference Algebraic Geometry in East Asia 2016)

The purpose of this paper is to investigate the close relation between Okounkov bodies and Zariski decompositions of pseudoeffective divisors on smooth projective surfaces. Firstly, we completely determine the limiting Okounkov bodies on such surfaces, and give applications to Nakayama constants and Seshadri constants. Secondly, we study how the shapes of Okounkov bodies change as we vary the divisors in the big cone., Comment: 16 pages, Changed Section 5 and corrected typos, to appear in Bull. Korean. Math. Soc. (special volume for Magadan Conference)

An Okounkov body is a convex subset in Euclidean space associated to a big divisor on a smooth projective variety with respect to an admissible flag. In this paper, we introduce two convex bodies associated to pseudoeffective divisors, called the valuative Okounkov bodies and the limiting Okounkov bodies, and show that these convex bodies reflect the asymptotic properties of pseudoeffective divisors as in the case with big divisors. Our results extend the works of Lazarsfeld-Musta\c{t}\u{a} and Kaveh-Khovanskii. For this purpose, we define and study special subvarieties, called the Nakayama subvarieties and the positive volume subvarieties, associated to pseudoeffective divisors., Comment: 24 pages. Final version. To appear in J. London Math. Soc

An Okounkov body is a convex subset of Euclidean space associated to a divisor on a smooth projective variety with respect to an admissible flag. In this paper, we recover the asymptotic base loci from the Okounkov bodies by studying various asymptotic invariants such as the asymptotic valuations and the moving Seshadri constants. Consequently, we obtain the nefness and ampleness criteria of divisors in terms of the Okounkov bodies. Furthermore, we compute the divisorial Zariski decomposition by the Okounkov bodies, and find upper and lower bounds for moving Seshadri constants given by the size of simplexes contained in the Okounkov bodies., Comment: 17 pages. Final version

We introduce the notion of potentially klt pairs for normal projective varieties with pseudoeffective anticanonical divisor. The potentially non-klt locus is a subset of $X$ which is birationally transformed precisely into the non-klt locus on a $-K_X$-minimal model of $X$. We prove basic properties of potentially non-klt locus in comparison with those of classical non-klt locus. As applications, we give a new characterization of varieties of Fano type, and we also improve results on the rational connectedness of uniruled varieties with pseudoeffective anticanonical divisor., Comment: 25 pages. We slightly modified the definitions of potentially klt pairs and potentially non-klt loci, and corrected a gap in the proof of Proposition 4.4

The purpose of the present paper is to generalize Sakai's work on anticanonical models of rational surfaces to varieties of Fano type. We first prove a characterization of Fano type varieties using the singularities of anticanonical models. Secondly, we study the decomposition of the anticanonical map using the $K_X$-minimal model program., Comment: 19 pages. We have corrected typos and mistakes. This will appear in IMRN

We prove that the cone of mobile divisors and the cone of curves birationally movable in codimension 1 are dual in the $(K+B)$-negative part for a klt pair $(X/Z,B)$. We also prove the structure theorem and the contraction theorem for the expanded cone of curves birationally movable in codimension 1. The duality of the cones gives a partial answer to the problem posed by Sam Payne., Comment: Clarified a few arguments

An introduction to geography of log models with applications to positive cones of FT varieties and to geometry of minimal models and Mori fibrations., Comment: 69 pages. Typos are corrected. Sections 6 and 7 are modified