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Zbl 1002.26004
Wesołowska, J.
On sets determined by sequences of quasi-continuous functions.
(English)
[J] J. Appl. Anal. 7, No.2, 271-283 (2001). ISSN 1425-6908; ISSN 1869-6082/e

Let $X$ be a topological space. $f: X\to\bbfR$ is said to be quasi-continuous iff for $p\in X$ and open sets $U\subset X$, $W\subset\bbfR$ such that $p\in U$, $f(p)\in W$, there is an open set $G\ne\emptyset$ such that $G\subset U$, $f(G)\subset W$. The main problem of the paper is to find conditions, for given sets $L_0$, $L_{+\infty}$, $L_{-\infty}$, assuring that there exists a sequence of quasi-continuous functions $f_n$ that is convergent on $L_0$, $f_n\to+\infty$ on $L_{+\infty}$ and $f_n\to-\infty$ on $L_{-\infty}$.
[Ákos Császár (Budapest)]
MSC 2000:
*26A15 Continuity and related questions (one real variable)
26A21 Classification of functions of one real variable
54C30 Real-valued functions on topological spaces
54C08 Generalizations of continuity

Keywords: quasi-continuity; cliquishness; sets of convergence points

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