graph parsetree1 { node [texmode="math",shape="none"]; S0 [label="S"]; T0 [label="T"]; S1 [label="S"]; a0 [label="a"]; S2 [label="S"]; b0 [label="b"]; T1 [label="T"]; S3 [label="S"]; T2 [label="T"]; S4 [label="S"]; spacer [label="",style="invisible"]; a1 [label="a"]; S5 [label="S"]; b1 [label="b"]; e0 [label="e",texlbl="$\varepsilon$"]; a2 [label="a"]; S6 [label="S"]; b2 [label="b"]; e1 [label="e",texlbl="$\varepsilon$"]; e2 [label="e",texlbl="$\varepsilon$"]; e3 [label="e",texlbl="$\varepsilon$"]; S0 -- T0; S0 -- S1; T0 -- a0; T0 -- S2; T0 -- b0; S1 -- T1; S1 -- S3; S2 -- T2; S2 -- S4; b0 -- spacer [style="invisible"]; T1 -- a1; T1 -- S5; T1 -- b1; S3 -- e0; T2 -- a2; T2 -- S6; T2 -- b2; S4 -- e1; S5 -- e2; S6 -- e3; }