@TechReport{Langdon98,
  author      = "William B Langdon and Riccardo Poli",
  title       = {Boolean Functions Fitness Spaces},
  institution = {University of Birmingham, School of Computer Science},
  number      = {CSRP-98-16},
  month       = {June},
  year        = {1998},
  email       = {W.B.Langdon@cs.bham.ac.uk, R.Poli@cs.bham.ac.uk},
  file        = {/1998/CSRP-98-16.ps.gz},
  url         = {ftp://ftp.cs.bham.ac.uk/pub/tech-reports/1998/CSRP-98-16.ps.gz},
  abstract    = {We investigate the distribution of performance of the
                 Boolean functions of 3 Boolean inputs (particularly that
                 of the parity functions), the always-on-6 and even-6
                 parity functions. We us enumeration, uniform Monte-Carlo
                 random sampling and sampling random full trees. As
                 expected XOR dramatically changes the fitness
                 distributions. In all cases once some minimum size
                 threshold has been exceeded, the distribution of
                 performance is approximately independent of program
                 length. However the distribution of the performance of
                 full trees is different from that of asymmetric trees and
                 varies with tree depth.
                 
                 We consider but reject testing the No Free Lunch (NFL)
                 theorems on these functions.
                 },
}