Trade union leaders have asked workers at Germany’s Postbank to authorize indefinite strikes against the bank after the latest round of collective bargaining talks fell short of a deal on wage and job security demands. Postbank, a subsidiary of German banking giant Deutsche Bank, has been negotiating for months with the German Bank Employees’ Association (DBV) and the trade union verdi, who together represent about 12,000 employees. If workers authorize further action against Postbank, then renewed strikes could begin anytime after May 3, according to DBV. There have already been a number of s…