📄️ Deterministic Finite Automaton
Deterministic Finite automaton (DFA) is a machine that can recognize a regular language based on its grammar.
📄️ Non-Deterministic Finite Automaton
Non-Deterministic Finite automaton (NFA) is an extension to the DFA that is simpler to design. It can be converted into a DFA and thus, it also accepts a regular language.
📄️ Non-Deterministic Finite Automaton With Empty Transitions
We have nullable regular languages, and so we have nullable NFA, that is, NFA with empty transitions, also called e-NFA ($\epsilon$-NFA).
📄️ Regular Expression
Regular expression is a simpler way to describe a regular language.
📄️ Left Linear Grammar
This is a bit of a detour. Previously, we defined regular grammar as,
📄️ Pumping Lemma of Regular Languages
The pumping lemma for regular languages is a lemma that describes an essential property of all regular languages. Informally, it says that all sufficiently long strings in a regular language may be pumped—that is, have a middle section of the string repeated an arbitrary number of times—to produce a new string that is also part of the language.