How to make the vertex $0$ frozen? I would like to define a quiver with the vertex $0$ frozen: Q = ClusterQuiver(DiGraph([[0,1],[1,2],[2,3],[2,4]]),frozen=0) But it seems that this doesn't work and the vertex $0$ is still mutable. How to make the vertex 0 frozen? Thank you very much.

I don't see any documentation of exactly how to use this in the documentation, but it does seem that it's the "number of frozen variables" so if you ask for zero frozen variables you get zero frozen variables? In particular, I doubt it corresponds directly to the vertices in this way. But I don't know much about cluster quivers!