Displaying similar documents to “Calabi-Yau threefolds of quasi-product type.”

On log canonical divisors that are log quasi-numerically positive

Shigetaka Fukuda (2004)

Open Mathematics

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Let (X Δ) be a four-dimensional log variety that is projective over the field of complex numbers. Assume that (X, Δ) is not Kawamata log terminal (klt) but divisorial log terminal (dlt). First we introduce the notion of “log quasi-numerically positive”, by relaxing that of “numerically positive”. Next we prove that, if the log canonical divisorK X+Δ is log quasi-numerically positive on (X, Δ) then it is semi-ample.

Ellis groups of quasi-factors of minimal flows

Joseph Auslander (2000)

Colloquium Mathematicae

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A quasi-factor of a minimal flow is a minimal subset of the induced flow on the space of closed subsets. We study a particular kind of quasi-factor (a 'joining' quasi-factor) using the Galois theory of minimal flows. We also investigate the relation between factors and quasi-factors.

Geography of log models: theory and applications

Vyacheslav Shokurov, Sung Choi (2011)

Open Mathematics

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This is an introduction to geography of log models with applications to positive cones of Fano type (FT) varieties and to geometry of minimal models and Mori fibrations.