Displaying similar documents to “The multiple conical surfaces.”

On the genus of reducible surfaces and degenerations of surfaces

Alberto Calabri, Ciro Ciliberto, Flaminio Flamini, Rick Miranda (2007)

Annales de l’institut Fourier

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We deal with a reducible projective surface X with so-called , which are a generalization of normal crossings. First we compute the p ω ( X ) of X , i.e. the dimension of the vector space of global sections of the dualizing sheaf ω X . Then we prove that, when X is smoothable, i.e. when X is the central fibre of a flat family π : 𝒳 → Δ parametrized by a disc, with smooth general fibre, then the ω -genus of the fibres of π is constant.

Atomic surfaces, tilings and coincidences II. Reducible case

Hiromi Ei, Shunji Ito, Hui Rao (2006)

Annales de l’institut Fourier

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The atomic surfaces of unimodular Pisot substitutions of irreducible type have been studied by many authors. In this article, we study the atomic surfaces of Pisot substitutions of reducible type. As an analogue of the irreducible case, we define the stepped-surface and the dual substitution over it. Using these notions, we give a simple proof to the fact that atomic surfaces form a self-similar tiling system. We show that the stepped-surface possesses the quasi-periodic...

Ruled W-surfaces in Minkowski 3-space ℜ 1 3

Rashad A. Abdel-Baky, H. N. Abd-Ellah (2008)

Archivum Mathematicum

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In this paper, we study a spacelike (timelike) ruled W-surface in Minkowski 3-space which satisfies nontrivial relation between elements of the set { K , K I I , H , H I I } , where ( K , H ) and ( K I I , H I I ) are the Gaussian and mean curvatures of the first and second fundamental forms, respectively. Finally, some examples are constructed and plotted.

Ruled W-surfaces in Minkowski 3-space ℜ 1 3

Rashad A. Abdel-Baky, H. N. Abd-Ellah (2008)

Archivum Mathematicum

Similarity:

In this paper, we study a spacelike (timelike) ruled W-surface in Minkowski 3-space which satisfies nontrivial relation between elements of the set { K , K I I , H , H I I } , where ( K , H ) and ( K I I , H I I ) are the Gaussian and mean curvatures of the first and second fundamental forms, respectively. Finally, some examples are constructed and plotted.

A note on a theorem of Xiao Gang.

Margarita Mendes Lopes (2004)

Collectanea Mathematica

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In 1985 Xiao Gang proved that the bicanonical surface of a complex surface S of general type with p2(S) > 2 is not composed of a pencil. In this note a new proof of this theorem is presented.