>So, the forms of cooperation are two - voluntary and involuntary.  
  
Let me offer an older argument  
  
This Corrective Justice again has two sub-divisions, corresponding to the   
two classes of private transactions, those which are voluntary and those   
which are involuntary. Examples of voluntary transactions are selling,   
buying, lending at interest, pledging, lending without interest, depositing,   
letting for hire; these transactions being termed voluntary because they are   
voluntarily entered upon. Of involuntary transactions some are furtive, for   
instance, theft, adultery, poisoning, procuring, enticement of slaves,   
assassination, false witness; others are violent, for instance, assault,   
imprisonment, murder, robbery with violence, maiming, abusive language,   
contumelious treatment.  
  
Aristotle, Nicomachean Ethics, Book V (On Justice), 1131a 1 et seq.  
  
> After all, Jack Benny knew that he had a choice when an armed robber   
> threatened him with, "Your money or your life!"  
  
Jack Benny apparently knew the meaning of optimization under constraint and   
corner(ed) solutions.  
  
  
Nicholas J. Theocarakis