How can I produce a Hasse (or lattice) diagram?

I want to produce a some kind of lattice diagram, such as a Hasse diagram. How can I do so? I tried using matrix with letters and slashes but it seems ugly. Do I need any additional packages?

EDIT: I mean graph like this one (for zessenhaous lemma):

-
what is a lattice, hasse graph? –  percusse Aug 22 '13 at 15:10
there are several packages that are intended to create such diagrams. someone will probably recommend tikz. xypic and pstricks also provide such capabilities. –  barbara beeton Aug 22 '13 at 16:56
In LyX, go to File > Open then go to examples, then click on "xypic.lyx". Similarly, you could try Help > Specific Manuals > XY-pic Manual (although this might have been added only in a recent version, I forget). Both documents are the same. –  scottkosty Aug 22 '13 at 22:53
–  Peter Grill Aug 23 '13 at 23:59

According to @barbarabeeton, here comes a possible PSTricks solution for the example you gave:

\documentclass[preview,border=3pt]{standalone}
\usepackage{pst-node}
\begin{document}
\psset{nodesep=3pt}
\newpsstyle{DblDash}{linestyle=dashed, dash=1pt 1.5pt, doubleline}
\begin{psmatrix}[mnode=r,colsep=0.6,rowsep=0.5]
[name=11] $A_1$ & & & & [name=12] $B_2$\\
& [name=21] $A(A_1\cap B_1)$ & & [name=22] $B(A_1\cap B_1)$ \\
& [name=31] $A(A_1\cap B)$ & [name=32] $A_1\cap B_1$ & [name=33] $B(A\cap B_1)$ \\
[name=41] $A$ & & [name=42] $D$ & & [name=43] $B$\\
& [name=51] $A\cap B_1$ & & [name=52] $A_1 \cap B$ \\
& & [name=61] $A\cap B$
\ncline{11}{21}\ncline{12}{22}
\ncline{21}{32}\ncline{22}{32}
\ncline[style=DblDash]{21}{31}
\ncline[style=DblDash]{22}{33}
\ncline{31}{41}\ncline{31}{42}\ncline{32}{42}\ncline{33}{42}\ncline{33}{43}
\ncline{41}{51}\ncline{42}{51}\ncline{42}{52}\ncline{42}{52}
\ncline{51}{61}\ncline{52}{61}
\end{psmatrix}
\end{document}


This gives the output:

-
@PSTikZ With pstricks the bounding box is wrong, it's far to large. –  Christoph Sep 5 '13 at 6:41