Separating sets by Darboux Baire 1 and approximately continuous functions |
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Authors: | Marcin Szyszkowski |
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Institution: | 1. WSB University, Gdańsk, Polandfox@mat.ug.edu.pl |
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Abstract: | We characterize sets A0, A1 for which there is a DB1 function f with f = 0] = A0 and f = 1] = A1. This characterization is a conjunction of necessary conditions for Darboux and for Baire 1 functions. We also characterize sets A?, A+ for which there is a DB1 function with f < 0] = A? and f > 0] = A+. The same characterzations are provided for approximately continuous functions. |
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Keywords: | 26A15 26A21 54C08 03E15 54H05 |
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