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Theorems · Inductive type · group theory

IsFreeGroupoid

(G : Type u_1) → [CategoryTheory.Groupoid G] → Type (max u_1 (v + 1))

A groupoid G is free when we have the following data: - a quiver on IsFreeGroupoid.Generators G (a type synonym for G) - a function of taking a generating arrow to a morphism in G - such that a functor from G to any group X is uniquely determined by assigning labels in X to the generating arrows. This definition is nonstandard. Normally one would require that functors G ⥤ X to any _groupoid_ X are given by graph homomorphisms from generators.

Defined in
Mathlib.GroupTheory.FreeGroup.NielsenSchreier
Cited by
11 results in Mathlib
Foundations
Depth 1 from the axioms · uses no axioms
Assumes
CategoryTheory.Groupoid

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