TITLE

# Points of joint continuity and large oscillations

AUTHOR(S)
Maslyuchenko, V.; Nesterenko, V.
PUB. DATE
December 2010
SOURCE
Ukrainian Mathematical Journal;Dec2010, Vol. 62 Issue 6, p916
SOURCE TYPE
DOC. TYPE
Article
ABSTRACT
For topological spaces X and Y and a metric space Z, we introduce a new class $\mathcal{N}\left( {X \times Y,\,Z} \right)$ of mappings f: X Ã— Y â†’ Z containing all horizontally quasicontinuous mappings continuous with respect to the second variable. It is shown that, for each mapping f from this class and any countable-type set B in Y, the set C( f) of all points x from X such that f is jointly continuous at any point of the set { x} Ã— B is residual in X: We also prove that if X is a Baire space, Y is a metrizable compact set, Z is a metric space, and $f \in \mathcal{N}\left( {X \times Y,\,Z} \right)$, then, for any Îµ > 0, the projection of the set D( f) of all points p âˆˆ X Ã— Y at which the oscillation Ï‰( p) â‰¥ Îµ onto X is a closed set nowhere dense in X.
ACCESSION #
55642644

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