Rules for Constructing Dual Problems
Maximisation Model in Canonical Form

The following general rules apply for constructing the dual problem for a maximisation model in canonical form:

The objective of the dual is minimisation.The primal’s RHS constants become the dual problem’s objective function coefficients

  • The primal’s objective function coefficients become the dual problem’s RHS constants.
  • When the primal has n variables, the dual has n constraints. The constraint coefficients of the j-th dual constraint are the constraint coefficients of the j-th primal variable.
  • When the primal has m constraints, the dual has m variables. The i-th dual variable is associated with the i-th primal constraint.
  • All dual constraints are  type.
  • All dual variables are nonnegative.


    • Forming General Dual Problems
    The constraint types of one model affect the variables’ sign restrictions of its dual. The variables’ sign restrictions of one model affect the constraint types of its dual.

    Maximisation Model
    Minimisation Model