Carlos Batalla Cordero believes in ticket scalping _ believes in it so strongly that he's founded a union and gone on a hunger strike to promote honest, legal scalping. Batalla Cordero has been keeping a vigil at the doors of the Metropolitan Cathedral here since Tuesday without eating. He has asked for a meeting with President Miguel de la Madrid to press his case for legalization. Ticket scalping is illegal, but it is much more common here than in the United States. At almost any popular movie, scalpers called ``resellers'' buy tickets and sell them for a premium to latecomers or to those who don't want to stand in line at the box office. Batalla Cordero, looking thin and unshaven during a Friday interview, said he thought legalization might reduce some abuses. ``There are three people in Mexico City who have about 70 people working for them who resell tickets for as much as 1,000 percent more than they paid,'' said Batalla Cordero. He said they will sometimes try to buy up all the tickets to an event to push up the resale price. ``They mistreat and cheat their customers,'' said Batalla Cordero. He said he believes scalpers should be limited to a 20 percent premium on the face value of the ticket. Nowadays, a ticket to a popular play can cost $19 and be resold for as much as $86. Batalla has founded a union that claims about 80 members. The union, called the Authentic Union of Independent Ticket Resellers in the Service of the Public for Theater, Cinema and Spectacles, has an office in Mexico City. ``The authorities have told me they won't answer my request for an interview with the president until Monday,'' said Batalla Cordero. Scalping was legalized in Mexico in 1952 but was outlawed again in 1961. Telephone calls to the press offices at the National Palace on Friday afternoon were not answered. Police at the cathedral said they had not seen Batalla Cordero eat anything, although he has been taking liquids.