Introduction to Turing machine

1. TOPIC : TURING MACHINE
Submitted by: Prabhat Ranjan
Reg No: 201302022
Course: B.Tech CSE (GEN) ,5TH Sem

2. What is Turing
Machine?
•A Turing Machine is a mathematical model of computation describing
an abstract machine that manipulates symbols on a strip of tape
according to a table of rules.
•Despite the model’s simplicity , it is capable of implementing any
computer algorithm.

3. Overvie
w
• A turing machine is a general example of a central processing unit(CPU) that
control all data manipulation done by a computer, with the canonical machine
used sequential memory to store data.
• It is a machine(automaton) capable of enumerating some arbitrary subset
of valid strings of an alphabet; these strings are part of a recursively
enumerable set.

4. Details to visualise Turing
Machine
• There will need to be many decisions on what the symbols actually look like, and
a failproof way of reading and writing symbols indefinitely.
• The shift left and shift right operations may shift the tape head across the tape,
but when actually building a Turing machine it is more practical to make the tape
slide back and forth under the head instead.
• The tape can be finite, and automatically extended with blanks as needed (which
is closest to the mathematical definition), but it is more common to think of it as
stretching infinitely at one or both ends and being pre-filled with blanks except on
the explicitly given finite fragment the tape head is on.

5. Universal Turing
Machine
As Turing wrote in The Undecidable, p. 128 (italics added):
It is possible to invent a single machine which can be used to compute
any computable sequence. If this machine U is supplied with the tape
on the beginning of which is written the string of quintuples separated
by semicolons of some computing machine M, then U will compute the
same sequence as M.

6. Limitations of Turing
Machine
• Computational complexity theory
• Concurrency
• Interaction

7. THANK YOU