Foreword. Packing Problems in Semigroup Programming (J. Aráoz). A Greedy Algorithm for Solving Network Flow Problems in Trees (P. Brucker). A Dual Optimality Criterion for Algebraic Linear Programs (P. Brucker, W. Papenjohann and U. Zimmermann). On Properties of Solution Sets of Extremal Linear Programs (P. Butkovič). Using Fields for Semiring Computations (R.A. Cuninghame-Green). Scheduling by Non-Commutative Algebra (R.A. Cuninghame-Green and W.F. Borawitz). Pseudo-Boolean Functions and Stability of Graphs (C. Ebenegger, P.L. Hammer and D. de Werra). Independence Systems and Perfect k-Matroid Intersections (R. Euler). Matroids on Ordered Sets and The Greedy Algorithm (U. Faigle). An Algorithm for the Unbounded Matroid Intersection Polyhedron (A. Frank and E. Tardos). Algebraic Flows (A.M. Frieze). Linear Algebra in Dioids; A Survey of Recent Results (M. Gondran and M. Minoux). Algebraic Flows and Time-Cost Tradeoff Problems (H.W. Hamacher and S. Tufekci). Ranking the Cuts and Cut-Sets of a Network (H.W. Hamacher, J.-C. Picard and M. Queyranne). Shortest Paths in Signed Graphs (P. Hansen). A Boolean Algebraic Analysis of Fire Protection (B.L. Hulme A.W. Shiver and P.J. Slater). Iteration and Summability in Semirings (B. Mahr). Substitution Decomposition for Discrete Structures and Connections with Combinatorial Optimization (R.H. Möhring and F.J. Radermacher). On Max-Separable Optimization Problems (K. Zimmermann). Minimization of Combined Objective Functions on Integral Submodular Flows (U. Zimmermann).