| Article ID: | iaor20061407 | 
| Country: | United States | 
| Volume: | 30 | 
| Issue: | 4 | 
| Start Page Number: | 985 | 
| End Page Number: | 1004 | 
| Publication Date: | Nov 2005 | 
| Journal: | Mathematics of Operations Research | 
| Authors: | Gowda M. Seetharama, Tao Jiyuan | 
In this article, we introduce the concepts of P and P