Wall Street mixed in early trading, with enthusiasm checked

Stocks are mixed in tentative early trading on Wall Street Tuesday, as investors wait to see how well the lifting of lockdowns around the world goes.The S&P 500 and other U.S. indexes were flipping between small gains and losses, following up on mixed performances in Europe and Asia. Treasury yields were down slightly, but a measure of nervousness in the U.S. stock market also touched its lowest level in two months.Governments around the world and in many U.S. states have begun gradually lif