An artificial chemistry is a computer model used to simulate various types of systems. The name comes from the fact that an artificial chemistry is in some ways similar to a chemical reaction. Artificial chemistry originated in artificial life but has shown to be a versatile method with applications in many fields such as chemistry, economics, sociology and linguistics.

Formal definition

An artificial chemistry is defined in general as a triple (S,R,A). In some cases it is sufficient to define it as a tuple (S,I).

• S is the set of possible molecules S={s₁...,s_n}, where n is the number of elements in the set, which could be infinite.

• R is a set of n-ary operations on the molecules in S, the reaction rules R={r₁...,r_n}. Each rule r_i is written like a chemical reaction a+b+c->a*+b*+c*, note here that r_i are the operators and not +.

• A is an algorithm describing how to apply the rules R to a proper subset PS.

• I is interaction rules of the molecules in S.

Different kinds of artificial chemistries

• depending on the space of possible molecules
  • finite
  • infinite

• depending on the type of reactions
  • cathalitic systems
  • reactive systems

• depending on the space topology
  • well stirred reactor

Important concepts

• organizations: An organization is a set of molecules that is closed and self-maintaining. As such, it is a set that does not create anything outside itself, and such that any molecule inside the set can be generated within the set.
• closed sets
• self maintaining sets
• hasse diagram of organizations

History of artificial chemistries

Artificial Chemistries came as a sub field from Artificial Life, in particular from Strong Artificial Life. The idea behind this field was that if we wanted to build something alive, this had to be a combination of non living entities. As a cell is itself alive, and yet is a combination of non living molecules. So artificial chemistry was the field that collected (among others) the researcher that believed in an extreme bottom up approach to artificial life.

Important contributors

The first reference about artificial Chemistries come from a Technical paper written by John McCaskill. Walter Fontana working with Leo Buss then took up the work developing the AlChemy model. The model was presented at the second International Conference of Artificial Life. In his first papers he presented the concept of organization, as a set of molecules that is algebraically closed and self maintaining.

Two main school of artificial chemistries have been (and still are) Japan, and Germany. In Japan the main researchers have been Ideaki SuzukiHikegami. In Germany, Dortmund hosted Wolfgang Banzhaf, which, as a professor worked with Peter Dittrich and Jens Ziegler, and they wrote the paper 'Artificial Chemistries a review' which bacame a standard in the field. Jens Ziegler, as part of his PhD thesis, proved that an artificial chemistry could be used to control a small kepera robot. Peter Dittrich first developed the Seceda model that through some simple rules could explain group forming in society, then became a professor and started his group in Jena where he investigated Artificial Chemistries as a way to define a general theory of Constructive Dynamical Systems.

Applications of artificial chemistries

Artificial Chemistries are often used in the study of protobiology, trying to gap the distance between Chemistry and Biology. Another main reason of being for Artificial Chemistries are the study of Constructive Dynamical System.

External links and references

• Artificial chemistries--a review(pdf file) (http://www.comp.nus.edu.sg/~cs6211/papers/artchemreview.pdf)