Editing Left recursion (section)

=== Indirect left recursion ===
Indirect left recursion occurs when the definition of left recursion is satisfied via several substitutions.  It entails a set of rules following the pattern
:<math>A_0 \to \beta_0A_1\alpha_0</math>
:<math>A_1 \to \beta_1A_2\alpha_1</math>
:<math>\cdots</math>
:<math>A_n \to \beta_nA_0\alpha_n</math>
where <math>\beta_0, \beta_1, \ldots, \beta_n</math> are sequences that can each yield the [[empty string]], while <math>\alpha_0, \alpha_1, \ldots, \alpha_n</math> may be any sequences of terminal and nonterminal symbols at all.  Note that these sequences may be empty.  The derivation
:<math>A_0\Rightarrow\beta_0A_1\alpha_0\Rightarrow^+ A_1\alpha_0\Rightarrow\beta_1A_2\alpha_1\alpha_0\Rightarrow^+\cdots\Rightarrow^+ A_0\alpha_n\dots\alpha_1\alpha_0</math>
then gives <math>A_0</math> as leftmost in its final sentential form.