Displaying 121 – 140 of 249

Showing per page

On glueing curves on surfaces and zero cycles

Hursit Önsiper (1994)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

The structure of the group H 2 X , K 2 of a surface X with prescribed singularities is investigated.

On the genus of reducible surfaces and degenerations of surfaces

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

Annales de l’institut Fourier

We deal with a reducible projective surface X with so-called Zappatic singularities, which are a generalization of normal crossings. First we compute the ω -genus 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.

On the Jung method in positive characteristic

Olivier Piltant (2003)

Annales de l’institut Fourier

Let X ¯ be a germ of normal surface with local ring R ¯ covering a germ of regular surface X with local ring R of characteristic p > 0 . Given an extension of valuation rings W / V birationally dominating R ¯ / R , we study the existence of a new such pair of local rings R ¯ ' / R ' birationally dominating R ¯ / R , such that R ' is regular and R ¯ ' has only toric singularities. This is achieved when W / V is defectless or when [ W : V ] is equal to p

Currently displaying 121 – 140 of 249