digraph N {
 graph [fontname="Helvetica" nodesep=0.25 ranksep="0.25" remincross=true label="Petri net\nΩ=((p4=0) ∧ (init=0) ∧ (p3=0) ∧ (p9=0) ∧ (p2=0) ∧ (final=0) ∧ (p5=0) ∧ (p7=0) ∧ (p1=0) ∧ (p8=0) ∧ (p6=0))"]
 node [fontname="Helvetica" fixedsize width=".3" height=".3" label="" style=filled]
 edge [fontname="Helvetica" color=white arrowhead=none weight="20.0"]

// interface

// places
 node [shape=circle fillcolor=white]
p10 []
 p10_l  [style=invis]
 p10_l -> p10 [headlabel="final"]
p11 [fillcolor=black peripheries=2 height=".2" width=".2" ]
 p11_l  [style=invis]
 p11_l -> p11 [headlabel="init"]
p1  []
 p1_l   [style=invis]
 p1_l -> p1 [headlabel="p1"]
p6  []
 p6_l   [style=invis]
 p6_l -> p6 [headlabel="p2"]
p4  []
 p4_l   [style=invis]
 p4_l -> p4 [headlabel="p3"]
p7  []
 p7_l   [style=invis]
 p7_l -> p7 [headlabel="p4"]
p2  []
 p2_l   [style=invis]
 p2_l -> p2 [headlabel="p5"]
p3  []
 p3_l   [style=invis]
 p3_l -> p3 [headlabel="p6"]
p5  []
 p5_l   [style=invis]
 p5_l -> p5 [headlabel="p7"]
p9  []
 p9_l   [style=invis]
 p9_l -> p9 [headlabel="p8"]
p8  []
 p8_l   [style=invis]
 p8_l -> p8 [headlabel="p9"]
 // transitions
 node [shape=box]
t7  []
 t7_l   [style=invis]
 t7_l -> t7 [headlabel="t1"]
t1  []
 t1_l   [style=invis]
 t1_l -> t1 [headlabel="t2"]
t6  []
 t6_l   [style=invis]
 t6_l -> t6 [headlabel="t3"]
t8  []
 t8_l   [style=invis]
 t8_l -> t8 [headlabel="t4"]
t4  []
 t4_l   [style=invis]
 t4_l -> t4 [headlabel="t5"]
t5  []
 t5_l   [style=invis]
 t5_l -> t5 [headlabel="t6"]
t2  []
 t2_l   [style=invis]
 t2_l -> t2 [headlabel="t7"]
t3  []
 t3_l   [style=invis]
 t3_l -> t3 [headlabel="t8"]

 // inner cluster
 subgraph cluster1
 {
  t7 t7_l t1 t1_l t6 t6_l t8 t8_l t4 t4_l t5 t5_l t2 t2_l t3 t3_l
  p10 p10_l p11 p11_l p1 p1_l p6 p6_l p4 p4_l p7 p7_l p2 p2_l p3 p3_l p5 p5_l p9 p9_l p8 p8_l
  label="" style=invis
 }

 // arcs
 edge [fontname="Helvetica" arrowhead=normal color=black]
 t3 -> p10  []
 p11 -> t7  []
 t7 -> p1   []
 p1 -> t1   []
 t7 -> p6   []
 p6 -> t6   []
 t1 -> p4   []
 p4 -> t8   []
 t6 -> p7   []
 p7 -> t4   []
 t6 -> p2   []
 p2 -> t5   []
 t4 -> p3   []
 t8 -> p3   []
 p3 -> t2   []
 p5 -> t2   []
 t5 -> p5   []
 p9 -> t3   []
 t2 -> p9   []
 t2 -> p8   []
 p8 -> t3   []








}