This is an announcement for the paper "Separable reduction theorems by the method of elementary submodels" by Marek Cuth.
Abstract: We introduce an interesting method of proving separable reduction theorems - the method of elementary submodels. We are studying whether it is true that a set (function) has given property if and only if it has this property with respect to a special separable subspace, dependent only on the given set (function). We are interested in properties of sets ``to be dense, nowhere dense, meager, residual or porous'' and in properties of functions ``to be continuous, semicontinuous or Fr'echet differentiable''. Our method of creating separable subspaces enables us to combine our results, so we easily get separable reductions of function properties such as ``be continuous on a dense subset'', ``be Fr'echet differentiable on a residual subset'', etc. Finally, we show some applications of presented separable reduction theorems and demonstrate that some results of Zajicek, Lindenstrauss and Preiss hold in nonseparable setting as well.
Archive classification: math.FA
Mathematics Subject Classification: 46B26, 03C30
Remarks: 27 pages
Submitted from: cuthm5am@karlin.mff.cuni.cz
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1101.1627
or