Editing Gene expression programming (section)

====Inversion====
Inversion is an interesting operator, especially powerful for [[combinatorial optimization]].<ref>{{cite web|last=Ferreira|first=C.|year=2002|title=Combinatorial Optimization by Gene Expression Programming: Inversion Revisited|url= http://www.gene-expression-programming.com/webpapers/Ferreira-ASAI02.pdf|publisher= In J. M. Santos and A. Zapico, eds., Proceedings of the Argentine Symposium on Artificial Intelligence, pages 160–174, Santa Fe, Argentina}}</ref> It consists of inverting a small sequence within a chromosome.

In gene expression programming it can be easily implemented in all gene domains and, in all cases, the offspring produced is always syntactically correct. For any gene domain, a sequence (ranging from at least two elements to as big as the domain itself) is chosen at random within that domain and then inverted.