Combinatorics is the branch of pure mathematics that studies collections of objects that satisfy specified criteria. Loosely defined, combinatorics is the science of counting.

### Recommended Resources

Advanced Process Combinatorics

APC was organized as a partnership of Purdue University and industry professionals, and specializes in the application of mathematical programming based optimization to the process industries, one of its primary products being VirtECS, and work in combinatorics.

http://www.combination.com/

The Annals of Combinatorics publishes contributions to combinatorial mathematics, with special attention to new developments in the field, as well as applications to computer science, biology, statistics, probability, physics, chemistry, and works of a combinatorial nature in representation theory, number theory, algebraic geometry, and the theory of special functions. Other resources include conference and seminar schedules, and information about people and groups in the field.

http://www.combinatorics.net/

CFS is an academic institution for combinatorial research and intellectual inquiry in China, its research activities raining from the theoretical to the applied, covering a range of fields across combinatorics and graph theory. Its research projects are discussed, along with its publications, educational programs, and other activities.

http://www.combinatorics.cn/

Electronic Journal of Combinatorics

The EJC is a fully-refereed online journal that publishes papers from all branches of discrete mathematics, including combinatorics, graph theory, discrete algorithms, and related topics. All volumes of the publication are available, along with surveys and submission guidelines.

http://www.combinatorics.org/