Time-Frequency Analysis of Sj\"ostrand's Class
  We investigate the properties an exotic symbol class of pseudodifferential operators, Sj\"ostrand's class, with methods of timne-frequency analysis (phase space analysis). Compared to the classical treatment, the time-frequency approach leads to striklingly simple proofs of Sj\"ostrand's fundamental results and to far-reaching generalizations. 
Karlheinz Gr\"ochenig