https://en.wikipedia.org/wiki/Earley_parser
An input string of length $n$ is syntactically correct if at least one $(S \rightarrow X_1 ... X_m • 0)$ is in $E_n$. Why is this the case ? The part before the dot (•) represents the subpart of the rule that derives a substring of the input string starting at position $i + 1$. Shouldn't the statement be:
An input string of length $n$ is syntactically correct if at least one $(S \rightarrow X_1 ... X_m • n)$ is in $E_n$ since I have parsed all the words before ? I.e, $n$ instead of 0.
