I think tradeoff has to be positive-sum. 有得必有失
		
		
		
		 所有跟贴·加跟贴·新语丝读书论坛http://www.xys.org/cgi-bin/mainpage.pl 
		
		送交者: skipper3 于 2005-10-04, 11:24:53:
回答: 拉2说 由 葛观 于 2005-10-04, 10:51:13:
can be zero-sum even negative-sum.
 
所有跟贴:
加跟贴
	
 所有跟贴·加跟贴·新语丝读书论坛http://www.xys.org/cgi-bin/mainpage.pl