We present a generic tool, called FMona, for expressing validation methods, we illustrate its use through the expression of the abstraction technique and its application to infinite or parameterized space problems. After a review of the basic results concerning transition systems, we show how abstraction can be expressed within FMona and used to build a reduced system with decidable properties. The FMona tool is used to express the validation steps leading to synthesis of a finite abstract system then SMV and/or Mona validate its properties.