The main aim of this survey paper is to give basic information about properties and applications of -porous sets in Banach spaces (and some other infinite-dimensional spaces). This paper can be considered a partial continuation of the author's 1987 survey on porosity and -porosity and therefore only some results, remarks, and references (important for infinite-dimensional spaces) are repeated. However, this paper can be used without any knowledge of the previous survey. Some new results concerning -porosity in finite-dimensional spaces are also briefly mentioned. However, results concerning porosity (but not -porosity) are mentioned only exceptionally.
"On $\sigma$-porous sets in abstract spaces." Abstr. Appl. Anal. 2005 (5) 509 - 534, 30 June 2005. https://doi.org/10.1155/AAA.2005.509