  The growth-fragmentation equation arises in many different contexts, ranging
from cell division, protein polymerization, biopolymers, neurosciences etc.
Direct observation of temporal dynamics being often difficult, it is of main
interest to develop theoretical and numerical methods to recover reaction rates
and parameters of the equation from indirect observation of the solution.
Following the work done in (Perthame, Zubelli, 2006) and (Doumic, Perthame,
Zubelli, 2009) for the specific case of the cell division equation, we address
here the general question of recovering the fragmentation rate of the equation
from the observation of the time-asymptotic solution, when the fragmentation
kernel and the growth rates are fully general. We give both theoretical results
and numerical methods, and discuss the remaining issues.
