PlanetPhysics/Generator

Let us consider an [[../AbelianCategory2/|abelian category]] $𝒞$. Then, an [[../TrivialGroupoid/|object]] $G$ of $𝒞$ is called a generator if $Ho{m}_{𝒞}(G,A)$ is nonzero for every nonzero object $A$ of $𝒞$.