In trying to plot a graph, I came across a serious inconvenience with styling and plotting edges which seems a bit odd and pretty unexpected.

The documentation (Help) says, and we knew, that the last style specification overrides the previous. But there is nothing in the Help about the fact that multiple edges between two vertices are considering to be unique (just one edge, just the same) for some purposes and not for others. As the issue is hard to explain in plain text, I have attached one notebook which presents the problem in some detail. The notebook is a bit redundant, a bit colourful, and perhaps inelegant and baroque, but has been made so in purpose to fully explain what happens; or, at least, which is the difficulty I am facing.

It seems that the multiple edges feature has been released uncompleted and without warning on this issue. Or perhaps it is just a bug. The issue conveys a lot of inconvenience in dealing with multiple edges, because, for example, in the case I present in the notebook:

• The system represented by the graph happens to be highly complex and highly important despite its apparent simplicity. Everything in it carry a lot of meaning.

• Plotting the different packages (categories) of edges separately in different graphs hides much key information about the whole system. There are not three graphs (three systems) there is just one, and all the elements with their own colours must be plotted and make visible.

• The whole view of the system, plotted in one graph, explains at first sight how it works. Right applied colours are a must.

• It is not just the lines (graphical edges) which matter, both the vertex and the edges properties and other attached stuff to them are critical to the graph (system) representation. If the elements are hidden all the information attached to them is hidden too, and lost.

In the attached notebook the much of the whole issue will be found, and any suggestion would be very appreciate.

Thanks.

Martin.

P.S.

I beg your pardon for posting the following text here, but I did not find the appropriate place to post it.