I'm unable to see your attachment, but if I understand what you want, the simplest approach is to create "phantom" nodes in the tree. This can be achieved with "child [missing]" as in the following examples:
First, a simple tree with two nodes: A and B; A is the root, and B is directly below it: \begin{tikzpicture} \node {A} child {node {B}}; \end{tikzpicture} Then with node B towards the left: \begin{tikzpicture} \node {A} child {node {B}} child [missing]; \end{tikzpicture} and now, with B towards the right: \begin{tikzpicture} \node {A} child [missing] child {node {B}}; \end{tikzpicture} Now, with your example (I changed the numbers in the nodes, for reference): \begin{tikzpicture} \node {$1.~\neg ((p \lor (p \land q)) \limp p)$} child {node {$2.~ p \lor (p \land q)$} child [missing] child {node {$3.~ \neg p $} child {node {$4.~ \ p $}} child {node {$5.~ p \land q$} child [missing] child {node {$6.~ p $} child {node {$7.~ q $}} child [missing]}}}} child [missing]; \end{tikzpicture} As indicated in the examples above, the position of the "child [missing]" relative to its siblings determines where you get the child nodes. Of course you can also add any number of missing children, which increases the angle: \begin{tikzpicture} \node {A} child [missing] child [missing] child {node {B}}; \end{tikzpicture} Furthermore, you can control the distance between sibling nodes: \begin{tikzpicture}[sibling distance=4cm] \node {A} child {node {B}} child {node {C}}; \end{tikzpicture} and even the distance between levels: \begin{tikzpicture}[sibling distance=4cm,level distance=5cm] \node {A} child {node {B}} child {node {C}}; \end{tikzpicture} On Mon, Oct 28, 2013 at 4:06 PM, William Hanson <whan...@umn.edu> wrote: > Dear LyX Colleagues, > > I'm still trying to create tableau proofs, which are branching columns of > text, as illustrated in the attachment. > > Ernesto Posse's sample tableau (below) is helpful, but it contains two > features I don't want: > > 1. Two sentences at a node, separated by commas. I want just one > sentence at each node, as in the attached sample. I've been figured out > how to solve this problem by modifying Ernesto's code as follows: > > \def\land{\wedge} > \def\lor{\vee} > \def\limp{\to} > \begin{tikzpicture} > \node {$1\neg ((p \lor (p \land q)) \limp p)$} > child {node {$ 1 p \lor (p \land q)$} > child {node {$1 \neg p $} > child {node {$1 \ p $}} > child {node {$1 p \land q$} > child {node {$1 p $} > child {node {$1 q $}}}}}}; > \end{tikzpicture} > > 2. But the foregoing code retains another feature I don't want: vertical > lines from node to node when there is no branching. I want only the > (approximately) 45 degree (and 315 degree) lines that indicate branching, > as on the attached sample. > > I've used LyX for several years, but I don't know LaTeX. > > Any and all help appreciated. > > Bill > > > > > > [image: Sample > Tableau.pdf]<https://mail.google.com/mail/u/0/?ui=2&ik=fcb7343f58&view=att&th=141e0e8e8016ae7f&attid=0.1&disp=safe&realattid=f_hn3bnlm80&zw> > *Sample Tableau.pdf* > 146K > View<https://docs.google.com/viewer?a=v&pid=gmail&attid=0.1&thid=141e0e8e8016ae7f&mt=application/pdf&authuser=0&url=https://mail.google.com/mail/u/0/?ui%3D2%26ik%3Dfcb7343f58%26view%3Datt%26th%3D141e0e8e8016ae7f%26attid%3D0.1%26disp%3Dsafe%26realattid%3Df_hn3bnlm80%26zw&sig=AHIEtbQpDR5qvKd2TSh_O5cOhrpoG-Owmg> > Download<https://mail.google.com/mail/u/0/?ui=2&ik=fcb7343f58&view=att&th=141e0e8e8016ae7f&attid=0.1&disp=safe&realattid=f_hn3bnlm80&zw> > > Ernesto Posse <epo...@cs.queensu.ca> > Oct 22 (6 days ago) > > to me, lyx-users > Hello. The easiest (and nicest) way to do this is using the tikz package: > in the preamble put > > \usepackage{tikz} > > and then, wherever you want the tableau, put in a TeX box the following: > > \def\land{\wedge} > > \def\lor{\vee} > > \def\limp{\to} > > \begin{tikzpicture} > > \node {$\{\neg ((p \lor (p \land q)) \limp p)\}$} > > child {node {$\{p \lor (p \land q), \neg p\}$} > > child {node {$\{p\}$}} > > child {node {$\{p \land q\}$} > > child {node {$\{p,q\}$}}}}; > > \end{tikzpicture} > > > Note that the structure of the tree depends on the grouping braces { ... }. > > > Richard Heck <rgh...@lyx.org> > Oct 22 (6 days ago) > > to Ernesto, me, lyx-users > There are lots of useful resources about this here: > http://www.logicmatters.net/latex-for-logicians/trees/ > > > > > > > > > > > > > > > > > > > -- Ernesto Posse Modelling and Analysis in Software Engineering School of Computing Queen's University - Kingston, Ontario, Canada