Decision theory

The decision theory proposes a set of mathematical tools helping decision making in medium random and risked and making it possible to guide the decision makers in their choice.
Most economic decisions are caught in environments dubious or fixed with the risk. The economic agents make decisions of which they are unaware of the consequences and are strongly based on processes of choice and arbitration.
Decide results from a combination of two processes: a process of perception and a process of optimization. The process of perception makes it possible to the individual to select the elements which seem relevant him - elements on which it wishes to base his decision - and to organize them. The process of optimization makes it possible as for him to solve a problem such as it emanates from a process of perception. It is thus, a theory which rests on the induction i.e. which generalizes the experiments passed to explain and solve a problem present. It estimates from this point of view the case present compared to the case passed in their allotting a utility according to his waitings and according to the constraints of each case. It is process allows decision making in a more rational way vis-a-vis a problem by comparing the experiments or acts at its disposal with the case present to leave a result it.
This can be formalized in a function which one will call function of similarity represented as follows:
C=P X A X R

With: * C= the case * P= the problem * A=selected act * R=result
This similarity depends of course on the context and must be everywhere similar with something meadows if one it multiple as many times as possible by a positive number (Gilboa and Scheimdler, 2001).
This agent has a memory from which it can draw completely and instantaneously. This memory suggests to him that, similar problems P (noted q1, q2, q3, etc) associated actions A (noted a1, a2, a3, etc) and made it possible to get a result R (r1, r2, r3,