## Combinations

This chapter describes functions for creating and manipulating
combinations. A combination c is represented by an array of
k integers in the range 0 to n-1, where each value
c_i occurs at most once. The combination c corresponds to
indices of k elements chosen from an n element vector.
Combinations are useful for iterating over all k-element subsets
of a set.

The functions described in this chapter are defined in the header file
`gsl_combination.h`

.