The document discusses the concept of a Post machine, a simplified version of a Turing machine introduced by Emil Post in 1936, which serves as a model for universal algorithm computation. It outlines its history, properties such as its alphabet, storage mechanisms, and state configurations, and provides an example of processing the input string 'aaabbb'. The machine operates based on specific rules for reading and accepting strings, including the use of a special end-of-input symbol.

1. Post Machine

2. Objective:
• Introduction.
• History
• Properties
• Example
• Explaination

3. Post Machine:
A Post–Turing machine is a "program
formulation" of an especially simple type of
Turing machine, comprising a variant of
Emil Post's Turing-equivalent model of
computation.

4. History:
In 1936 introduced the Turing machine , Emil
Leon Post (1897-1954) created the Post
Machine, which the hoped would prove to be
the “universal algorithm machine ”. One
condition must b satisfied by such a “universal
algorithm machine “ is that any language
which can b precisely defined by humans
should be accepted by some version of this
machine.

5. Properties:
1. The alphabet of input letters plus the
special symbol #.
2. A linear storage location called the Store or
Queue, which initially contains the input
string(using FIFO and LIFO stack).
3. Read states.
.

6. 1. Add states.
1. A start state and some halt states called
ACCEPT or REJECT.

7. Example:
Let us trace the processing of the input aaabbb on this
PM.

9. Explanation:
The # is used as an end-of-input string signal. In
READ1 we check to see weather we are out of output;
we reading the end-of- input signal #. if we accept
the string .if we read ab , the string crashes. So
nothing starting with ab is accepted. If the string start
with an a, this letter is consumed by READ1 :the trip
from READ 1 to READ2 cost one a that is not replaced.
The loop at READ2 puts the rest of the a’s from the
front cluster of a’s behind the #.the first b read is
consumed in the trip from READ2 to READ3.At
READ3 the rest of the first cluster of b’s is stripped off
the front and appended onto the back , behind the a’s
that are behind the #.Therefore , the language
accepted by the PM.