A note on theories with a minimal length

The aim of this note is to clarify the relation between three different approaches of theories with a minimal length scale: a modification of the Lorentz group in the 'deformed special relativity', theories with a 'generalized uncertainty principle' and those with 'modified dispersion relations'. It is shown that the first two are equivalent, how they can be translated into each other, and how the third can be obtained from them. An adequate theory with a minimal length scale requires all three features to be present.