code: def delta(x_i, j, s, N):
          
          flag = j == EMMMixPLAggregator.c(x_i, s)
          if flag and s < len(x_i):
              return 1
          elif s == N:
              found_equal = False
              for l in range(len(x_i)):
                  if j == EMMMixPLAggregator.c(x_i, l):
                      found_equal = True
                      break
              if not found_equal:
                  return 1
          return 0
docs: delta_i_j_s