1. Formal Language

2. Structure description of sentences in Computer is Formal Language.
Mathematical model for defining computer language.

3. Definition of Grammar:-

4. Some Rules:- 1) Reverse substitution is not allowed.
S AB is production then we can replace S by AB but we can not replace AB by S.
2) No Inversion operation is allowed.
S AB is production then it is not necessary that AB S is a production.

5. Derivation and the Language Generated by a Grammar:-Q1

6. Q2. Q3.

7. Q4.

8. Q5.

9. Q6.

10. Chomsky classification of Language:- Type 0 :-
Example:-

11. Type 1:-
Example:-

13. Type 2:-
Type 3:-

14. Example Q.:-

15. Language and Their Relation:-

17. Recursive and Recursively Enumerable Sets:-

18. Example

19. Operations on Language:-

20. Language and Automata:-