Category
page 1Lemmas in set theory
Zorn's lemma
statement equivalent to the axiom of choice, about the existence of a maximal element in a poset with a maximal chain condition
Mostowski collapse lemma
theorem
Teichmüller–Tukey lemma
lemma that states that every nonempty collection of finite character has a maximal element with respect to inclusion
Rasiowa–Sikorski lemma
mathematical lemma
Fodor's lemma
lemma