In the published version of this article [Reference Meir1], the author’s second affiliation appeared incorrectly. The affiliation should appear as follows:
INSTYTUT MATEMATYCZNY, UNIWERSYTETU WROCŁAWSKI
PL. GRUNWALDZKI 2/4, 50-384 WROCŁAW, POLAND
The publisher apologizes for the error. The article has been corrected online to rectify this error.