Comment on ``On Existence of a Biorthonormal Basis Composed of   Eigenvectors of Non-Hermitian Operators [quant-ph/0603075]''
  We point out that T. Tanaka's recent criticism [quant-ph/0603075] of the results of J. Math. Phys. 43, 3944 (2002) [math-ph/0203005] is based on an assumption which was never made in the latter paper, namely that the diagonalizability of an operator implies that it is normal. Therefore, Tanaka's objections regarding this paper are not valid. 
Ali Mostafazadeh