Canonical-grandcanonical ensemble in-equivalence in Fermi systems?
  I discuss the effects of fermionic condensation in systems of constant density of states. I show that the condensation leads to a correction of the chemical potential and of the Fermi distribution in canonical Fermi systems at low temperatures. This implies that the canonical and grandcanonical ensembles are not equivalent even for Fermi systems. 
Dragos-Victor Anghel