  In a recent paper (quant-ph/0506105), A S Gupta, M. Gupta and A. Pathak
proposed a modified Grover algorithm that would exponentially accelerate the
unsorted database search problem if the number of marked items is known. If
this were true, it would represent a major fundamental breakthrough in computer
science, mathematics, quantum information and other related branches of
sciences.
  However the algorithm is not valid. We will explain it in this brief comment.
