Flips from 4-folds with isolated complete intersection singularities whose downstairs have rational bi-elephants
Abstract
Description
We shall investigate a flipping contraction g : X -> Y from a 4-fold X with at most isolated complete intersection singularities. If Y has an anti-bi-canonical divisor (=bi-elephant) with only rational singularities, then g carries an inductive structure chained up by blow-ups (La Torre Pendente), and in particular the flip exists. This naturally contains Miles Reid's `Pagoda' as an anti-canonical divisor (=elephant) and its proper transforms.
Free picture (photocopy, 1 sheet) is available, write me your name and postal address at kachi@math.utah.edu (by June 28)
Free picture (photocopy, 1 sheet) is available, write me your name and postal address at kachi@math.utah.edu (by June 28)