Characterization of sigma-porosity via an infinite game

Abstrakt

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 sigma-P-porous sets in X.

This characterization can be applied to ordinary porosity above all but also to many other variants of porosity.

Klíčová slova

• infinite games
• sigma-porosity
• porosity