OpenAI announced a joint venture with Japan’s SoftBank on Monday, with the investment giant spending $3 billion a year to use OpenAI software, in an apparent change of strategy following DeepSeek’s unexpected rise.The Chinese firm’s cutting-edge artificial intelligence model uses only a fraction of the computing power of OpenAI’s ChatGPT and similar products, upending widespread assumptions about the technical and financial requirements of AI expansion. Meanwhile, the AI firm’s CEO Sam Altman sa...