Nvidia’s boss dismisses fears that AI has hit a wall

WHEN SAM ALTMAN, boss of OpenAI, posted a gnomic tweet this month saying “There is no wall,” his followers on X, a social-media site, had a blast. “Trump will build it,” said one. “No paywall for ChatGPT?” quipped another. It has since morphed from an in-joke among nerds into a serious business matter.