A Note on Inverse-preservations of Regular Open Sets


Takashi Noiri


In this note an example is given in order to show that the following lemma is false (Kovačević [3]): If $f:X\to Y$ is an almost-continuous and almost-closed function, then $f^{-1}(V)$ is regular open (resp. regular closed) in $X$ for every regular open (resp. regular closed) set $V$ of $Y$.