abstract = "In this paper we use the schema theory presented
elsewhere in this volume to better understand the
changes in size distribution when using GP with
standard crossover and linear structures. Applications
of the theory to problems both with and without fitness
suggest that standard crossover induces specific biases
in the distributions of sizes, with a strong tendency
to over sample small structures, and indicate the
existence of strong redistribution effects that may be
a major force in the early stages of a GP run. We also
present two important theoretical results: An exact
theory of bloat, and a general theory of how average
size changes on flat landscapes with glitches. The
latter implies the surprising result that a single
program glitch in an otherwise flat fitness landscape
is sufficient to drive the average program size of an
infinite population, which may have important
implications for the control of code growth.",
notes = "'sec 1.2 Why theory matters Six years ago McPhee and
Miller \cite{McPhee:1995:acrep} examined bloat in the
INC-IGNORE problem, an artificial problem ... only
taken out 100 generations ... in a new run taken out to
3000 generations ... shows a much more complex picture
... it is unclear [what] the long term behavior
[is].'