2022/11/21 by Beri, Pietro, Manivel, Laurent · 1 citation
#Algebraic Geometry (math.AG) #FOS: Mathematics
paper · doi:10.48550/arxiv.2211.12866
Given a general K3 surface S of degree 18, lattice theoretic considerations allow to predict the existence of an anti-symplectic birational involution ϕ of the Hilbert cube S[3]. We describe this involution in terms of the Mukai model of S, with the help of the famous transitive action of the exceptional group G2(R) on the six-dimensional sphere. We make a connection with Homological Projective Duality by showing that the indeterminacy locus of the involution is birational to a P2-bundle over the dual K3 surface of degree two. We deduce that ϕ is an instance of a Mukai flop.