Elon Musk and Sam Altman appeared in federal court in Oakland Tuesday to hear their lawyers begin what is expected to be a month-long trial to decide the future of OpenAI, the frontier artificial intelligence developer.

Sam Altman and Elon Musk are facing off in a high-stakes trial that could alter the future of OpenAI and its most well-known product, ChatGPT.

Mr. Musk says that Mr. Altman and other OpenAI executives tricked him into giving money to start OpenAI as a nonprofit lab that was supposed to be dedicated to making A.I. that was safe for humanity.