Formal Language And Its Type.finite automata and formal languages

Formal Language And Its Type.finite automata and formal languages

https://www.gyanodhan.com/video/7B3.%20GATE%20CSEIT/Theory%20of%20Computation/617.%20Formal%20Language%20And%20Its%20Type.finite%20automata%20and%20formal%20languages.mp4

Formal Language and Its Types | Finite Automata and Formal Languages

Formal language and automata theory form the mathematical foundation of computer science, especially compiler design, language processing, and artificial intelligence.

---

What is a Formal Language?

A formal language is a set of strings made from a finite alphabet and governed by specific syntactic rules. It is used to define and analyze languages that computers can process.

• Alphabet (Σ): A finite set of symbols (e.g., Σ = {0,1})
• String: A finite sequence of symbols from an alphabet
• Language (L): A set of strings over an alphabet (L ⊆ Σ*)

---

Types of Formal Languages (Chomsky Hierarchy)

Language Class	Automaton / Recognizer	Grammar Type	Example Language
1⃣ Regular Languages	Finite Automata (FA)	Type 3 – Regular	Binary numbers divisible by 3
2⃣ Context-Free Languages	Pushdown Automata (PDA)	Type 2 – CFG	Balanced parentheses ((()))
3⃣ Context-Sensitive	Linear Bounded Automata (LBA)	Type 1 – CSG	a^n b^n c^n where n ≥ 1
4⃣ Recursively Enumerable	Turing Machine (TM)	Type 0 – Unrestricted	All computable languages

---

Finite Automata (FA)

Used to recognize regular languages. There are two main types:

1. DFA (Deterministic Finite Automaton)

• One unique path for each input symbol
• No ε (epsilon) transitions

2. NFA (Non-Deterministic Finite Automaton)

• Multiple paths allowed for a single input
• Can include ε-transitions

Formal Definition of DFA:

DFA = (Q, Σ, δ, q0, F)
Q  = set of states
Σ  = input alphabet
δ  = transition function (Q × Σ → Q)
q0 = initial state
F  = set of accepting states

---

Applications of Formal Languages

• Design of compilers and interpreters
• Lexical analysis using regular expressions
• Pattern matching, string searching (grep, regex)
• Natural language processing
• Design of protocols, algorithms, and AI models

---

Want a Video in Hindi?

You can watch an explanation on YouTube:
Formal Language and Automata Theory in Hindi – Part 1

---

Need PDF Notes or a Short Course?

Let me know and I can create or recommend:

• Handwritten notes
• PPTs or PDFs
• GATE/NET/UGC-level MCQs
• Short quizzes for practice

Would you like that?

Formal Language And Its Type.finite automata and formal languages

UNIT – I – Formal Language and Automata – SMT1404

An Introduction to Formal Languages and Automata

FORMAL LANGUAGES AND AUTOMATA THEORY

DIGITAL NOTES ON FORMAL LANGUAGES AND …

Formal Languages and Automata Theory

Formal Languages and Automata Theory.