A Note Related to a Paper of Noiri
Publications de l'Institut Mathématique, _N_S_36 (1984) no. 50, p. 103
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In [4] Noiri gave a counterexample to Lemma 1.1 in [1] which
reads: If $f:X\to Y$ is an almost closed and almost continuous mapping,
then $f^{-1}(V)$ is regularly open (regularly closed) in $X$ for each
regularly open (regularly closed) set $V$ in $Y$. In this
counterexample $f$ is not a surjection. There exists also another
counterexample, where $f$ is a surjection. There exists also another
counterexample, where $f$ is a surjection (Example 1 in [2]). But,
Lemma A is necessarily true if a new condition is added.