1. A WEIGTHED-PATH-FOLLOWING METHOD FOR THE LINEAR COMPLEMENTARITY PROBLEM. Authors: MOHAMED ACHACHE.2. ON THE APPROXIMATION NUMBERS OF CERTAIN VOLTERRA INTEGRAL OPERATORS BETWEEN LEBESGUE SPACES. Authors: MOHAMED ACHACHE.3. A PRIMAL-DUAL INTERIOR POINT ALGORITHM FOR CONVEX QUADRATIC PROGRAMS. Authors: MOHAMED ACHACHE.4. A WEIGHTED LOGARITHMIC BARRIER INTERIOR-POINT METHOD FOR LINEARLY CONSTRAINED OPTIMIZATION. Authors: SELMA LAMRI, BACHIR MERIKHI, MOHAMED ACHACHE.5. A TWO-STEPS FIXED-POINT METHOD FOR THE SIMPLICIAL CONE CONSTRAINED CONVEX QUADRATIC OPTIMIZATION. Authors: MOHAMED ACHACHE, MERZAKA KHALDI.