Formulations and Reformulations in Integer Programming

			    Michael Trick
		  
		    Bosch Professor and President
		       Carnegie Bosch Institute
		      Tepper School of Business
		   Carnegie Mellon University, USA


Integer programming is a valuable tool for modeling and solving
real-world problems.  Unfortunately, the first formulation almost
never works in practice!  Successful integer programming practice
involves a creative, iterative approach to formulation.  Drawing on
examples from network design, sports scheduling, and other
applications, I illustrate some of the reformulation tricks and
describe the theory underlying them.