On the Decomposition Group of a Nonsingular Plane Cubic by a Log Calabi-Yau Geometrical Perspective.

Abstract

This paper aims to study the decomposition group of a nonsingular plane cubic under the light of the log Calabi-Yau geometry. Using this approach we prove that an appropriate algorithm of the Sarkisov program in dimension 2 applied to an element of this group is automatically volume preserving. From this, we deduce some properties of the (volume preserving) Sarkisov factorization of its elements. We also confirm an expectation by Blanc, Pan and Vust on the splitting property of the canonical complex of a nonsingular plane cubic. Within a similar context in dimension 3, we exhibit in detail an interesting counterexample for a possible generalization of a theorem by Pan in which there exists a Sarkisov factorization obtained algorithmically that is not volume preserving.