# 1 – Aut | Notations

• $S=\NS(X)$ denotes the Néron-Severi lattice of the $K3$ surface $X$.
• $\LL$ denotes an even hyperbolic lattice.
• $\pl$ denotes the positive cone of $\LL$.
• $\ps$ denotes the positive cone of $S$.
• Denote by $\overline{C}$ the topological closure of a set $C$.