I'm trying to draw arrows with / marks and numbers like in the following picture:

My current solution looks like this:
\begin{tikzpicture}
[
inverter/.style={rectangle,draw,inner sep=2pt,minimum size=6mm},
dot/.style={circle,inner sep=0pt,minimum size=0.5mm,draw,fill=black}
]
\node (x) at (0,0) {$x$};
\node (delta) at (1,0) [shape=rectangle,draw,minimum height=18mm,minimum width=6mm] {$\delta$};
\node(ah) at ( 2, 0.5) [inverter] {$a_h$};
\node(al) at ( 2, -0.5) [inverter] {$a_l$};
\draw [->] (x) -- (delta);
\draw [->,dashed,dash pattern=on 1pt off 1pt] (delta.58.75) -- (ah);
\node at ($ (ah) - (0.55, 0) $) {\scriptsize /};
\node at ($ (ah) - (0.5, 0.2) $) {\tiny 4};
\draw [->,dashed,dash pattern=on 1pt off 1pt] (delta.-58.75) -- (al);
\node at ($ (al) - (0.55, 0) $) {\scriptsize /};
\node at ($ (al) - (0.5, 0.2) $) {\tiny 4};
\end{tikzpicture}
which is pretty hacky and doesn't look nice. I tried strike out shapes but found the line to be much too long. However, positioning a / and a number manually seems like a pretty bad solution to me. I've seen a similar question that revolved around striking out lines or arrows, but without any numbering. Any input would be most welcome.


4part of the slash or is it independent of it? And is it always a4? – Qrrbrbirlbel Jul 26 '13 at 07:40