Trading in the U.S. stock market seemed to have stabilized Friday after a disastrous session on Thursday, but fears of a Greek default continued to create anxiety in the markets. The Dow was trading just about flat in midafternoon. In Asia, stocks plunged early in the session but pared losses later. The Hang Seng index closed down 1.36 percent and the Nikkei in Japan fell 2 percent. European markets fell slightly, as fears of a global recession overshadowed G20 officials’ assertions hat they were committed to keeping the financial system stable.