• Preservation of Limits. We have an equality of sets
    \[ f_{!}\webleft (\bigcap _{i\in I}U_{i}\webright )=\bigcap _{i\in I}f_{!}\webleft (U_{i}\webright ), \]

    natural in $\webleft\{ U_{i}\webright\} _{i\in I}\in \mathcal{P}\webleft (A\webright )^{\times I}$. In particular, we have equalities

    \[ \begin{gathered} f^{-1}\webleft (U\cap V\webright ) = f_{!}\webleft (U\webright )\cap f^{-1}\webleft (V\webright ),\\ f_{!}\webleft (A\webright ) = B, \end{gathered} \]

    natural in $U,V\in \mathcal{P}\webleft (A\webright )$.


Noticed something off, or have any comments? Feel free to reach out!


You can also use the contact form below: