Graph incidence list implementation

Question

I'm considering graph data structure implementations and am looking at the "incidence list" representation. There is a brief description of it here:

Incidence list

So each vertex in the graph stores a list of those edges upon which it is incident.

Given that my graph is a digraph, I'm not very clear from this description on a couple of points:

1. Does the graph itself also store a list of all edges?
2. Do vertices only store outgoing edges, or incoming and outgoing?
3. If both, are they in separate lists?

I'm quite familiar with the other graph representations (adjacency list, adjacency matrix, edge list, incidence matrix), so this isn't a question about graph implementations in general, just this particular one.

Any pointers would be much appreciated.

Armand

Answer 1

Having researched and thought about it further, I've come to the conclusion that there isn't an incidence list graph data strucure. I think that the Wikipedia article was the product of some confusion in the author's mind. Thanks to everyone who read this question and spent any time on it.

Armand