SRKR Engineering College
Department of Computer Science and
Engineering, Bhimavaram, A.P. - 534204
FORMAL LANGUAGES & AUTOMATA THEORY
Outcomes
The student will be able to
Understand the Central Concepts of Automata Theory and
Finite Automation
Explain the Acceptance of a String by a Finite Automation
Finite Automata Example
Push
Switch
Start
Off
On
Push
Central Concepts of Automata
Languages: “A language is a
collection of sentences of finite
length all constructed from a finite
alphabet of symbols”
Grammars: “A grammar can be
regarded as a device that
enumerates the sentences of a
language” - nothing more,
nothing less
N. Chomsky, Information and
Control, Vol 2, 1959
8 75
Important Definitions
Alphabets
An Alphabet is a finite, non empty set of symbols.
Symbolized by ∑
∑ = {0,1}
∑ = {a,b,…….z}
Strings
A String is a finite sequence of symbols chosen from some
alphabet
0111, 110
cse, suresh, aaabb
Important Definitions
€
Length of a String
|w|
Powers of an Alphabet ∑k ∑*
Concatenation of Strings xy
Languages
Empty String
A set of strings all of which are chosen from some , where ∑ is
a particular alphabet. L
Examples of Languages
L of all strings consisting of n 0s followed by n 1s, for n>=0
Set of strings of 0s and 1s with an equal number of each
Set of binary numbers whose value is a prime
FINITE AUTOMATA
i) Input Tape
ii) Finite Control
iii) Read head
Acceptance of a string by FA
A finite automaton M is a 5- tuple (Q, Σ, δ, q0, F) consisting of finite
set of states (Q), finite set of input symbols (Σ), transition function (δ)
start state (q0∈ Q) and set of accept states (F)
0
