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Possible Duplicate:
Strange arrow mark with TikZ edge and anchors.

The following code

\begin{tikzpicture}
    \node (q0) [initial,state] {$q_0$};
    \node (q1) [state,right of=q0,accepting]    {$q_1$};
    \draw[->] (q1.south) edge node {$\varepsilon$} (q0.south);
\end{tikzpicture} 

gives

result

note the arrow-tip that appears at the arrow base (where it connects q1). it appears every time the source anchor is specified (ie. (q1.south) rather than (q1)). Specifying such an anchor for the arrow head (q0) works fine.

My workaround was drawing it white

\draw[->,white] (q1.south) edge[black,bend left] node {$\varepsilon$} (q0.south);

which is better, but a carful eye can still see a white arrow-tip at the arrow base.

marked as duplicate by TH., Gonzalo Medina, Caramdir, Jan Hlavacek, Martin Scharrer Apr 21 '11 at 9:28

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