Degressive proportionality – notes on the ambiguity of the concept

This article discusses the problem of the definition of degressive proportionality. This term is used in many areas of economics but its meaning is not standardized. It is understood differently when related to tax issues compared to distribution of seats in the European Parliament. The differences are small but significant. The article provides and analyzes the different meanings of the concept of degressive proportionality and proposes to introduce two new concepts – concave degressive proportionality and convex degressive proportionality.