Definiton of a certain symbol in a proof(The right linear languages are exactly the finite state languages) I want to stress that i am not looking for a proof of this question, but rather if someone(that is familiar with the proof and it's context) can explain to me what the symbol 'e' means in the context.



the letter 'e' first appears in line 6:S $\rightarrow $e...

This is crucial for me, because i am not able to deduct from the context what its meaning and write a formal proof
The letter $e$ stands the empty word, which is usually denoted by the symbol $\varepsilon$.
A hint of this is that, according to step 6, if $S \to e$ then the initial state $S$ is also a final state.