In the present paper, we study the problem of small-time
local attainability (STLA) of a closed set.
For doing this, we introduce a new concept of variations of the
reachable set well adapted to a given closed set and prove a new
attainability result
for a general dynamical system. This provide our main result for nonlinear
control systems. Some applications to linear and polynomial systems are
discussed and STLA necessary and sufficient conditions are obtained
when the considered set is a hyperplane.
