1. CS-300
Theory of Computation
2nd Sem 2017
Lecture 1

2. General Info for the Course
Instructor: Dr.Mohammad El-Bashir
Syllabus: tentative class schedule
can be found in course web page
Book: Introduction to the
Theory of Computation
Michael Sipser, 3rd edition
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3. Outline of the course contents
Computation
memory
CPU
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4. temporary memory input CPU output Program memory 2nd Sem 2017
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5. Example: temporary memory input CPU output Program memory compute
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6. temporary memory input CPU output Program memory compute compute
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7. temporary memory input CPU output Program memory compute compute
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8. temporary memory input CPU Program memory output compute compute
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9. Automaton temporary memory Automaton input CPU output Program memory
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10. Automaton temporary memory Automaton input output state transition
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11. Different Kinds of Automata
Automata are distinguished by the temporary memory
Finite Automata: no temporary memory
Pushdown Automata: stack
Turing Machines: random access memory
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12. Finite Automaton temporary memory input Finite Automaton output
Example: Elevators, Vending Machines
(small computing power)
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13. Pushdown Automaton Stack Push, Pop input Pushdown Automaton output
Temp.
memory
Stack
Push, Pop
input
Pushdown
Automaton
output
Example: Compilers for Programming Languages
(medium computing power)
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14. Turing Machine Random Access Memory input Turing Machine output
Temp.
memory
Random Access Memory
input
Turing
Machine
output
Examples: Any Algorithm
(highest computing power)
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15. Power of Automata Finite Automata Pushdown Automata Turing Machine
Simple
problems
More complex
problems
Hardest
problems
Finite
Automata
Pushdown
Automata
Turing
Machine
Less power
More power
Solve more
computational problems
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16. Turing Machine is the most powerful computational model known
Question: Are there computational
problems that a Turing Machine
cannot solve?
Answer: Yes
(unsolvable problems)
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17. Time Complexity of Computational Problems:
NP-complete problems
Believed to take exponential
time to be solved
P problems
Solved in polynomial time
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