olemus
hulga üldistus, võib elemente sisaldada mitme eksemplarina

Wiktionary:
a generalized type of set in which multiple occurrences of an element are permitted

näiteid
http://mathworld.wolfram.com/Multiset.html

ülevaateid
https://encyclopediaofmath.org/wiki/Multiset

https://en.wikipedia.org/wiki/Multiset

https://projecteuclid.org/download/pdf_1/euclid.ndjfl/1093634995

https://www.matec-conferences.org/articles/matecconf/pdf/2018/83/matecconf_icmtmte2018_04004.pdf