Tracking Issue: Digraph Targets

[Rida-Hamadani]

This is a list of things related to digraphs that would be nice to have.

• Weak and strong connectivity.

  • If vertices have equal in-degree and out-degree, then the digraph is weakly connected if and only if it is strongly connected.
  • Robbin's Theorem.

• Tournaments

  • A tournament has a Hamiltonian path.
  • A tournament has a Hamiltonian cycle If and only if it is strongly connected.

Many of the concepts that already exist in SimpleGraph should be ported to Digraph too.
Feel free to add digraph results that you would like to see formalized!