A long-running debate over how artificial intelligence (AI) should be developed has now turned into a major fight in Silicon Valley. Tech companies are now openly disagreeing over whether powerful AI models should be kept closed or made open for everyone to use. The divide is mainly between two groups. One group includes OpenAI and Anthropic, while the other includes Microsoft, Nvidia, Meta, IBM, Palantir and many AI start-ups.Why Silicon Valley is divided over Chinese AI as OpenAI, Microsoft and Nvidia clash over open-source AI, security, innovation and the US-China tech race. (AP Photo/Ng Han Guan) (AP Photo/Ng Han Guan)OpenAI…