gener intno given messag predecessor given messag successor represent given integ predecessor given messag successor parallel execut messag messag messag concurr activ us syntax like mean successor order list successor entri postfix second todo document except behaviour param uml messag uml messag object gener sequenc number param uml predecessor immedi predecessor messag uml object given messag successor param posit integ posit given messag sequenc gener sequenc express given messag gener messag number object uml messag object uml predecessor posit iter activ object uml activ subpo submax uml messag uml activ model facad activ uml messag uml activ activ gener messag number uml activ activ guarante uml predecessor order list immedi successor collect model facad successor uml predecessor submax size iter uml messag subpo builder result builder activ activ length result append result append posit submax result append subpo result 