Li Qin wrote: [ 2. "If A is the subclass of union of B and C" does not mean that A is the union of B and C. My question concerns the case that A is the union of B and C. If A is the union of B and C, the instances of B and C are instances of A. If A is the superclass of B and C, the instances of B and C are instances of A. What is the difference? 3. ...Does this unkown class the union of A and B or the superclass of A and B? ] Yuzhong Qu's reply [ * The properties of a superclass are applicable to the instances of the subclasses. * Just guess, use the union structure ] Pat Hayes 's comment: [ That is not quite correct. The properties which apply to the elements of a superclass are applicable to the instances of the subclasses: but that is because those instances are the very same things as the instances of the superclass. It is the union, which is a superclass of both. ] Does it mean that "If A is the union of B and C, then A is a superclass of both B and C"? Where does the entailment come from? Yuzhong Qu Dept.Computer Science and Engineering Southest University, Nanjing, China http://cse.seu.edu.cn/People/yzqu/enReceived on Sunday, 21 September 2003 22:28:04 GMT
This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 27 October 2009 08:34:56 GMT