code: @SuppressWarnings("unchecked")
      private void fixupMin(int k) {
          K key = array[k];
          int gp = k / 4;
          while (gp > 0 && ((Comparable<? super K>) array[gp]).compareTo(key) > 0) {
              array[k] = array[gp];
              k = gp;
              gp = k / 4;
          }
          array[k] = key;
      }
docs: Upwards fix starting from a particular element at a minimum level
  
  @param k
  the index of the starting element