K3 surfaces with a symplectic automorphism of order 4

Benedetta Piroddi

Given $X$ a K3 surface admitting a symplectic automorphism $\tau$ of order 4, we describe the isometry ${\tau }^{\ast }$ on $H^2(X,\mathbb{Z})$. Having called $\tilde{Z}$ and $\tilde{Y}$ respectivel…