It is done: After an agreement that there would be a second-in-command with actual education experience, the state Education Department has granted Mayor Bloomberg's pick Cathie Black a waiver to take over as the Schools Chancellor of the largest public school system in the country. The publishing executive has been a controversial choice but State Education Commissioner David Steiner wrote, "It is my judgment that, when viewed in its entirety, Ms. Black's training, background and experience are substantially equivilent to the certification requirements set forth in law."