digraph G { d2toptions="--autosize"; node [shape=circle]; a_1 [texlbl="$x^2+\frac{\sin y}{y^2+\cos \beta}+\gamma_3$"]; a_1 -> a_2 [label=" ", texlbl="$x_1+x_3^2+z+c+v~~$"]; a_2 -> a_1; a_2 -> a_3; a_3 [lblstyle="minimum size=4cm"]; }