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On the class of contra \(\lambda\)-continuous functions. (English) Zbl 1174.54349

A set \(A\) in a topological space \(X\) is called a \(\Lambda\)-set if it is the intersection of all its open supersets. A set which is the intersection of a \(\Lambda\)-set and a closed set is called \(\lambda\)-closed. The class of contra \(\lambda\)-continuous functions (the preimage of each open set is \(\lambda\)-closed) is introduced and several properties of these functions are investigated.

MSC:

54C10 Special maps on topological spaces (open, closed, perfect, etc.)
54D10 Lower separation axioms (\(T_0\)–\(T_3\), etc.)