# open mapping

Let $X$ and $Y$ be two topological spaces. A function $f:X\rightarrow Y$ is said to be open if $f(U)$ is open for each open subset $U$ of $X$.

Accordingly, if $f(C)$ is closed for each closed subset $C$ of $X$, we say that $f$ is closed.

Title open mapping OpenMapping 2013-03-22 13:12:45 2013-03-22 13:12:45 Koro (127) Koro (127) 4 Koro (127) Definition msc 54C10 open function closed function closed mapping