取整函数的性质

  1. $ \left\lceil \frac{k}{k_0}\right\rceil+ \left\lceil \frac{1-k}{k_0}\right\rceil=1$.
    参见李发刚. 陈豪. 劳惠敏. 吕善翔. New upper bounds and constructions of multi-erase locally recoverable codes.