Let X be an arbitrary metric space and P be a porosity-like relation on X. We describe an infinite game which gives a characterization of σ-P-porous sets in X. This characterization can be applied to ordinary porosity above all but also to many other variants of porosity.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-fm216-2-2,
author = {Martin Dole\v zal},
title = {Characterization of $\sigma$-porosity via an infinite game},
journal = {Fundamenta Mathematicae},
volume = {219},
year = {2012},
pages = {109-118},
zbl = {1246.28001},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm216-2-2}
}
Martin Doležal. Characterization of σ-porosity via an infinite game. Fundamenta Mathematicae, Tome 219 (2012) pp. 109-118. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm216-2-2/