无法理解CYK算法伪代码

我正在读关于CYK算法 https://en.wikipedia.org/wiki/CYK_algorithm，并且有一部分伪代码我无法理解。整个伪代码是：

let the input be a string S consisting of n characters: a1 ... an.
let the grammar contain r nonterminal symbols R1 ... Rr.
This grammar contains the subset Rs which is the set of start symbols.
let P[n,n,r] be an array of booleans. Initialize all elements of P to false.
for each i = 1 to n
  for each unit production Rj -> ai
    set P[i,1,j] = true
for each i = 2 to n -- Length of span
  for each j = 1 to n-i+1 -- Start of span
    for each k = 1 to i-1 -- Partition of span
      for each production RA -> RB RC
        if P[j,k,B] and P[j+k,i-k,C] then set P[j,i,A] = true
if any of P[1,n,x] is true (x is iterated over the set s, where s are all the indices for Rs) then
  S is member of language
else
  S is not member of language

这些部分是我感到困惑的：

    for each production RA -> RB RC
      if P[j,k,B] and P[j+k,i-k,C] then set P[j,i,A] = true

有人会对这些伪代码给出一些提示吗？

伪代码

For each production R_A → R_B R_C:

如果 P[j,k,B] 和 P[j+k,i-k,C] 则设置 P[j,i,A] = true

Should be interpreted in the following way. Suppose that it's the case that P[j, k, B] is true. That means that the string formed from k characters starting at position j can derived from the nonterminal R_B. If it's also the case that P[j + k, i - k, C] is true, then the string formed from the i - k characters starting at position j + k can be derived from nonterminal R_C. Therefore, since R_A → R_B R_C is a production, it's the case that the string formed from the i characters starting at position j can be derived from R_A.

我认为这可能有助于将该伪代码解释为

For each production R_A → R_B R_C:

如果 P[j,k,B] == true 且 P[j+k,i-k,C] == true，则设置 P[j,i,A] = true

希望这可以帮助！