Let Γ be a quiver.
An oriented cycle is a nontrivial path 𝑝 with dom𝑝=cod𝑝,
i.e. a non-identity endomorphism in the free categoryΓ――.
The quiver Γ is called acyclic iff it has no oriented cycles.
Properties
Γ is acyclic iff MorΓ―― is finite, or equivalently the path algebra is finite-dimensional.