# Draw multiple inheritance hierarchies

I have to draw multiple inheritance type hierarchies. The worst case is something like the following:

I used tables and tree-dvipsto draw these figures, but I am now looking for something that is xelatex compatible.

I started typesetting simple hierarchies with forrest, but for cases like the one above this seems to be overkill. I already found Is there a library for drawing object inheritance trees in TikZ? but the problem is more complicated since inheritance may involve two or more parent nodes.

So: Is there a package for this or a predefined style for forest?

If you don't ask for an automatic way, a TiKZ matrix and some foreach loops are enough:

\documentclass[tikz,border=3mm]{standalone}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
\matrix (A) [matrix of nodes, row sep=1cm, nodes={minimum width=2cm}]
{
arg1+ & arg4+ & arg2+& arg3+ & arg3- & arg4- & arg1- & arg2- \\
arg12-123-124 & arg-124-2-24 & arg1-12 & arg12-23 & arg0-2 \\
arg124 & arg123 & arg12 & arg24 & arg1 & arg2 & arg23 & arg0 \\
};

\foreach \i in {1,...,8}
\draw (link.south) -- (A-1-\i.north);

\foreach \i/\j in {1/1,1/3,3/1,3/2,3/4,5/2,5/3,5/5,6/5}
\draw (A-1-\i.south)--(A-2-\j.north);

\foreach \i/\j in {2/1,2/3,4/2,4/6,5/4,7/4,7/7,8/5,8/8}
\draw (A-1-\i.south)--(A-3-\j.north);

\foreach \i/\j in {1/1,1/2,1/3,2/1,2/3,2/4,2/6,3/3,3/5,4/3,4/7,5/6,5/8}
\draw (A-2-\i.south)--(A-3-\j.north);

\end{tikzpicture}
\end{document}