  Tsallis' non-extensive statistical mechanics is claimed to be the correct
tool to describe the behaviour of low-dimensional dissipative maps at the edge
of chaos. Indeed, many different approaches confirm that, for those systems,
the evolution is governed by power-laws, not exponential, trends; this
coincides with predictions from generalized thermostatistics. In this work,
however, we present some analytical considerations, supported also by some
simple numerical examples, suggesting the existence of contradictions within
this picture.
