S. F. Tayebnasab - Department of Mathematics, University of Sistan and Baluchestan, Zahedan, ‎Iran‎.
F. Hamidi - Department of Mathematics, University of Sistan and Baluchestan, Zahedan, ‎Iran‎.
M. Allahdadi - Department of Mathematics, University of Sistan and Baluchestan, Zahedan, ‎Iran‎.

This paper addresses a type of fully fuzzy bilevel linear programming (FFBLP) wherein all the coefficients and decision variables in both the objective function and constraints are triangular fuzzy numbers. This paper proposes a new simple-structured, efficient method for FFBLP problems based on crisp bilevel programming that yields fuzzy optimal solutions with unconstraint variables and parameters. some examples have been provided to illustrate these methods.

Bilevel linear programming, Triangular fuzzy numbers, Ranking ‎function, Optimal solution, Unconstrain variables