Porous sets and additivity of Lebesgue measure
The paper is devoted to the study of the following cardinal characteristics: add(\({\mathcal I})\), cov(\({\mathcal I})\), non(\({\mathcal I})\) and cof(\({\mathcal I})\) for the sigma ideal of \(\sigma\)-strongly symmetrically porous sets and of \(\rho\)-small sets. The author compares these characteristics with those similar cardinals associated with sigma ideals of null sets and of meager sets.
scientific article; zbMATH DE number 4179701