p

,

pp g p

re is no subtree in an elite RPN chromosome, such as xy*, no self-

r is implemented for this kind of elite RPN chromosome. If there

than one subunit (subtree) in this selected elite RPN chromosome,

em are randomly selected. After two submits have been randomly

an elite RPN chromosome is chopped into five segments, which

ssed as below, where ߠଵ and ߠଶ stand for two selected subunits

) for a swap operation, i.e., a single-chromosome crossover

,

ሺ߬

ߠଵ

ߤ

ߠଶ

ߩሻ

(8.3)

A new RPN chromosome of the single-chromosome crossover including the

es for the RPN shown in the upper panel of Figure 8.13. The boxes in the dark

d stand for the swapped subunits.

A new tree of single-chromosome crossover including branch nodes for the tree

gure 8.13(a). The boxes in the dark background stand for the swapped subunits.

w RPN chromosome is thus formulated using the following

, where ࣷ stands for a newly generated RPN chromosome. It can

hat two selected subunits have been swapped from their original

leading to a new RPN chromosome.