m-Hemi-metric: A function d defined over (m+1)-tuples of {1,...,n} that is invariant under permutation, equals 0 if any two elements are identical, is non-negative, and satisfies the m-hemi-metric triangle inequality.
m-Hemi-metric Cone (HMETmn): The polyhedral cone of all m-hemi-metrics for fixed m and n.
m-Partition Hemi-metric: For an unordered (m+1)-partition of {1,...,n}, d = 0 if any two elements belong to the same subset, and 1 otherwise.
m-Hemi-cut Cone (HCUTmn): The positive span of all m-partition hemi-metrics.