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Results tagged with set-theory
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user 2757
forcing, large cardinals, descriptive set theory, infinite combinatorics, cardinal characteristics, forcing axioms, ultrapowers, measures, reflection, pcf theory, models of set theory, axioms of set theory, independence, axiom of choice, continuum hypothesis, determinacy, Borel equivalence relations, Boolean-valued models, embeddings, orders, relations, transfinite recursion, set theory as a foundation of mathematics, the philosophy of set theory.
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votes
What are interesting families of subsets of a given set?
Even families of subsets closed under unions are interesting. The following conjecture of Peter Frankl has been open for 31 years:
Let $A$ be a finite set, and let $\mathcal{F}$ be a collection o …
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