Traders work on the floor of the New York Stock Exchange (NYSE) on May 6, 2026 in New York City. Spencer Platt | Getty Images LONDON — European stocks are expected to open in mixed territory on Monday as investors digest the latest impasse in peace negotiations between the U.S. and Iran. The U.K.'s FTSE index is seen opening 0.15% higher, with Germany's DAX and France's CAC 40  flat, and Italy's FTSE MIB down 0.13%, according to data from IG. Global markets will start the new trading week on a fragile note after U.S. President Donald Trump declared Iran's counterproposal to end the war in the Middle East as "unacceptable". Negotiators have received Iran's response to U.S. proposals for peace talks, with the Tehran regime demanding an end to the war on all fronts and the lifting of sanctions on the country, Iran's semi-official  Tasnim news agency said , citing an informed source.…