Varietà di Hankel, sottovarietà di G(r; m)
Families of Measurable Conic Sections in the Projective Space PR
In this note we prove the measurability of the family of non-degenerate conic sections in the projective space , obtained by cutting a non-degenerate quadratic cone by a linear variety of dimension two not containing the cone vertex.
Rational Surfaces of Kodaira Type IV
We study the geometry of a rational surface of Kodaira type IV by giving the nature of its integral curves of self-intersection less than zero, in particular we show that they are smooth and rational. Hence, under a reasonable assumption, we prove the finite generation of its monoid of effective divisor classes and in almost all cases its anticanonical complete linear system is of projective dimension zero and of self- intersection strictly negative. Furthermore, we show that if this condition is...
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