10480
Thus the axioms of Zermelo–Fraenkel set theory refer only to pure sets and prevent its models from containing urelements ( elements of sets that are not themselves sets ) .
 person: Zermelo–Fraenkel
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Zermelo–Fraenkel