As a general rule, possibilistic programming is a fuzzy mathematical
programming which deals with ambiguous coefficients in
objective functions and/or constraints. Hence, the proposed FDEA
model can be mentioned as a possibilistic programming model
which contains ambiguous coefficients in its objective function
and constraints (i.e. Constraints (11) and (13)). To facilitate solving
the FDEA model, it must be transformed to an auxiliary crisp model.
In order to do so, a possibilistic programming method proposed
by Jiménez et al. (2007) is applied to handle the ambiguousness
associated with the output indicators of the FDEA model. The
equivalent crisp model has been solved by the OSL optimization
solver in GAMS