This tag is for elementary questions on set theory, spanning topics usually found in introductory courses in set theory, in addition to review sections of graduate textbooks in the same field. Topics include intersections and unions, differences and complements, De Morgan's laws, Venn diagrams, relations and functions, countability and uncountability, etc. More advanced topics should use (set-theory) instead.

This tag is for elementary questions on set theory, focusing on material usually covered in undergraduate set theory texts. More advanced topics should use set-theory instead.

Topics include intersections and unions, De Morgan's laws, Venn diagrams, relations, functions, countability and uncountability, power sets, etc.