abstract = "Redundant mapping from genotype to phenotype is common
in evolutionary algorithms, especially in genetic
programming (GP). Such a redundancy can lead to
neutrality, where mutations to a genotype may not alter
its phenotypic outcome. The effects of neutrality can
be better understood by quantitatively analysing its
two observed properties, i.e., robustness and
evolvability. In this study, we examine a compact
Linear GP algorithm, characterize its entire genotype,
phenotype, and fitness networks, and quantitatively
measure robustness and evolvability at the genotypic,
phenotypic, and fitness levels. We investigate the
relationship of robustness and evolvability at those
different levels. We use an ensemble of random walks
and hill climbs to study how robustness and
evolvability and the structure of genotypic,
phenotypic, and fitness networks influence the
evolutionary search process.",