A1=activity(duration=>10),
A2=activity(duration=>20),
A3=activity(duration=>30),
A4=activity(duration=>18,requests=>[A1,A2]),
A5=activity(duration=>8 ,requests=>[A2,A3]),
A6=activity(duration=>3 ,requests=>[A1,A4]),
A7=activity(duration=>4 ,requests=>[A5,A6]),
visAllActs([A1,A2,A3,A4,A5,A6,A7]) ?


