AN ALTERNATIVE EXPLANATION OF DISJUNCTIVE FORMULATIONS

The purpose of this paper is to explain the property of Disjunctive Fo rmulations for Mixed Integer Programmes in a simpler way, relying on t he Linear Programme (LP) definition of a dual. Disjunctive Formulation s are contrasted with standard formulations. They have proved a very p owerful way of modelling Integer Programmes. If a 'complete' disjuncti ve formulation is carried out we have a model whose LP Relaxation yiel ds an integer solution. It is shown that a Disjunctive Formulation has a natural dual which is an LP. Therefore the dual of the dual is an L P representation of the original Disjunctive Model. It is in fact a Di sjunctive Formulation.