Let πi​as the projection to the orthogonal complement of {bj​}j=1i−1​.Then the basis is HKZ-reduced if it is size-reduced and ∣∣bi∗​∣∣=λ1​(πi​(L)). This definition gives us a relatively simple way to compute a HKZ-reduced basis by iteratively finding the shortest vector in orthogonal projections.