abstract = "We propose and study new search operators and a novel
node representation that can make GP fitness landscapes
smoother. Together with a tree evaluation method known
as sub-machine-code GP and the use of demes, these make
up a recipe for solving very large parity problems
using GP. We tested this recipe on parity problems with
up to 22 input variables, solving them with a very high
success probability.",
notes = "p40 'GP-UX, a homologous operator .. in some cases it
can lead to the phenomenon of lexical convergence
whereby a suboptimal gene becomes fixed at a given
location.'