Shigetaka Fukuda

activity

19982004

collaborators

7 papers

math.AG2004

On the projective fourfolds with almost numerically positive canonical divisors

Shigetaka Fukuda

Let $X$ be a four-dimensional projective variety defined over the field of complex numbers with only terminal singularities. We prove that if the intersection number of the canonic…

math.AG2003

On log canonical divisors that are log quasi-numerically positive

Shigetaka Fukuda

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 term…

math.AG2003

A note on the ampleness of numerically positive log canonical and anti-log canonical divisors

Shigetaka Fukuda

In this short note, we consider the conjecture that the log canonical divisor (resp. the anti-log canonical divisor) $K_{X} + Δ$ (resp. $- (K_{X} + Δ)$ ) on a pair $(X, Δ)$ consisting of…

math.AG2001

Tsuji's Numerically Trivial Fibrations and Abundance

Shigetaka Fukuda

We apply Tsuji's theory of numerically trivial fibrations to the abundance problem.

math.AG2000

On Numerically Effective Log Canonical Divisors

Shigetaka Fukuda

Let $(X, Δ)$ be a 4-dimensional log variety which is proper over the field of complex numbers and with only divisorial log terminal singularities. The log canonical divisor $K_{X} + Δ$ …

math.AG1999

Decomposition of log crepant birational morphisms between log terminal surfaces

Shigetaka Fukuda

We prove that every log crepant birational morphism between log terminal surfaces is decomposed into log-flopping type divisorial contraction morphisms and log blow-downs. Repeatin…