Nvidia (NVDA -2.20%) is ideally positioned to be a major player in the market for physical artificial intelligence (AI), a technology that lets autonomous machines such as cars and robots understand, navigate, and interact with the real world. Nevertheless, certain hedge fund billionaires sold shares in the first quarter: Meanwhile, those same hedge fund managers, and others, bought Uber Technologies (UBER -2.10%), a company well positioned to benefit from robotaxis and whose stock has soared 300% in the pa ...