Hematologic and lymphoid disorders include multiple subgroups, which are determined by the following methods: Cytology, histology,
immune phenotyping, cytogenetics, molecular genetics. Especially the definition of lymphomas becomes more and more complicated, being continuously revised based on the most recent data. Because of the complex nature of these disorders verbal definitions may sometimes lead to ambiguity A mathematical approach may help to avoid that. Boolean algebra also sometimes called “mathematical logic” has been demonstrated to be a helpful for disease definition.