Chapter 1. A Unified Framework for a Class of Mathematical Programming Problems (Dipti Dubey) -- Chapter 2. Maximizing spectral radius and number of spanning trees in bipartite graphs (Ravindra B. Bapat) -- Chapter 3. Optimization problems on acyclic orientations of graphs, shellability of simplicial complexes, and acyclic partitions (Masahiro Hachimori) -- Chapter 4. On ideal minimally non-packing clutters (Kenji Kashiwabara) -- Chapter 5. Symmetric Travelling Salesman Problem (Tiru Arthanari) -- Chapter 6. About the links between equilibrium problems and variational inequalities (D. Aussel) -- Chapter 7. The shrinking projection method and resolvents on Hadamard spaces (Yasunori Kimura) -- Chapter 8. Some Hard Stable Marriage Problems: A Survey on Multivariate Analysis (Sushmita Gupta) -- Chapter 9. Approximate Quasi-Linearity for Large Incomes (Mamoru Kaneko) -- Chapter 10. Cooperative Games in Networks under Uncertainty on the Costs (L. Mallozzi) -- Chapter 11. Pricing competition between cell phone carriers in a growing market of customers (Andrey Garnaev) -- Chapter 12. Stochastic games with endogenous transitions (Reinoud Joosten).