HONG KONG — South Korea’s Kospi index plunged nearly 11 per cent on Tuesday on heavy selling of computer chipmaking stocks that have been battered recently by waves of fears that the boom in artificial intelligence may turn out to be a bubble. European shares opened moderately higher after a day of losses for most Asian markets, while U.S. futures were mixed.Oil prices declined more than 2 per cent. Trading was temporarily halted at times as Kospi dropped to its lowest level since April, closing 10.8 per cent lower at 6,023.66. Shares in chipmaker Samsung Electronics sank 13.4 per cent…