Lemmas

theorem for proving more complex theorems

mathematical sentence

lemma that a topological space is normal iff any 2 disjoint closed subsets can be separated by a continuous function

A trilemma is a difficult choice from three options, each of which is (or appears) unacceptable or unfavourable. There are two logically equivalent ways in which to express a trilemma: it can be expressed as a choice among three unfavourable options, one of which must be chosen, or as a choice among three favourable options, only two of which are possible at the same time.

type of pumping lemma

identity in Itô calculus analogous to the chain rule

lemma stating that a module homomorphism between two simple modules over the same ring is either an isomorphism or identically zero

lemma giving a property shared by all context-free languages

approach in statistical testing

Family closed under complements and countable unions of disjoint sets

given a cover of a metric space, a positive real number δ such that any set of diameter smaller than δ is a subset of a member of the cover

Analyzes the topology of a manifold by studying differentiable functions on that manifold

generalization of the pumping lemma for context-free languages

mathematical treatise attributed to Archimedes

Mathematical result

theorem

lemma proving that a set of events with limited dependence has positive probability of all happening together

Statement in mathematical logic

group with trivial abelianization

lemma

lemma

The tetralemma is a figure that features prominently in the logic of India.

proof in topology

Theorem

theorem in topology

theorem

lemma that every open subset of the reals is a countable union of open intervals

lemma