Linear bounded automata are a type of automaton that operates like a Turing machine but with a tape bounded by the length of the input string. They are more powerful than pushdown automata but less powerful than Turing machines. The computation is restricted to a constant bounded area between left and right end markers on the tape. Linear bounded automata accept context sensitive languages.

1. LINEAR BOUNDED
AUTOMATA (LBA)
SHAHANA P
ROLL NO : 27

2.  It behaves as a Turing machine but storage space of tape is restricted only to length of input string.
 It is less powerful than TM and more powerful than PDA.
 The computation is restricted to the constant bounded area.
 The input alphabet contain two special symbols which serve as left end marker and right end marker
which means the transition neither move to left of the left end marker nor to right of the right end marker.
 Linear bounded automata accepts context sensitive language.

3. A linear bounded automaton can be defined as an 8-tuple (Q, X, ∑, q0, ML, MR, δ, F) where −
•Q is a finite set of states
•X is the tape alphabet
•∑ is the input alphabet
•q0 is the initial state
•ML is the left end marker
•MR is the right end marker where MR ≠ ML
•δ is a transition function which maps each pair (state, tape symbol) to (state, tape symbol, Constant ‘c’) where c
can be 0 or +1 or -1
•F is the set of final states

5. LBA – APPLICATIONS
 For implementation of genetic programming
 For constructing syntactic parse tree for semantic analysis for the compiler
EXPRESSIVE POWER OF VARIOUS AUTOMATA
Expressive power can be determined from the class or set of languages accepted by that particular type
of machine. Here is the increasing sequence of expressive power of machines.

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