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Cell["Program 06-04: Probability generating function", "Section",
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Cell["\<\
The probability generating function G for the simple birth and death process \
for equal birth and death rates \[Lambda] is given by eqn (6.24). The first \
input defines G but time has been made dimensionless by putting \[Tau]=\
\[Lambda]t:\
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truncated at n=30. The initial population is ",
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Cell["\<\
The following shows a graph of the distributions for \[Tau]=1,2,3,4,5.\
\>", "Text",
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Cell["\<\
Higher values for \[Tau] seem to confirm that extinction is certain for this \
model in which the birth and death parameters are equal.\
\>", "Text",
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