Lahmar-benbernou A., Martinez A.
On Helffer-Sj\"ostrand's Theory of Resonances
(47K, LATeX 2e)

ABSTRACT.  We construct a simplified version of the microlocal theory of resonances
given by B. Helffer and J. Sj\"ostrand in \cite{HeSj1}. This new version
is based on
elementary microlocal exponential estimates, and permits to recover
their main results without the
use of their special pseudodifferential calculus and Fourier-integral
operators.