Uniform matroid

The graphic matroid of the cycle graph C₄, which is the uniform matroid $U{}_{4}^{3}$. More generally, the graphic matroid of C_n is $U{}_{n}^{n-1}$.

In mathematics, a uniform matroid is a matroid in which the independent sets are exactly the sets containing at most r elements, for some fixed integer r. An alternative definition is that every permutation of the elements is a symmetry.