There are often many ways to formulate mathematically an optimization problem.
The efficiency obtained in solving a given model may depend on the formulation
used. This is why a lot of research is directed on the reformulation of optimization
problems. It is sometimes interesting to increase the number of integer variables
and constraints. For a more comprehensive study of mathematical programming approaches
(resp. constraint programming techniques), the reader may refer to Refs
[37,300,686] (resp. [34,287,664]).