OpenAI’s president, Greg Brockman, right, was also named in Mr. Musk’s lawsuit.

The federal courthouse in Oakland, Calif., on Monday, when a jury decided that Elon Musk had waited too long to file his lawsuit against OpenAI.

In the trial’s first day of testimony in the OpenAI trial, Elon Musk said greed led Sam Altman, a founder of OpenAI, to pull the A.I. lab away from its nonprofit roots. OpenAI disagrees.

Elon Musk arriving at the Ronald V. Dellums U.S. Courthouse in Oakland Tuesday.

In January, Defense Secretary Pete Hegseth published a memo calling on A.I. to be widely integrated across the military and for A.I. companies to offer their technology without restrictions.

The new talks between Sam Altman and OpenAI’s board were the latest twist in a fast-moving drama at what is perhaps the world’s highest-profile artificial intelligence company.

The senior executives of OpenAI in March. From left, Mira Murati, now the company’s interim chief executive; Sam Altman, the ousted chief executive; Greg Brockman, OpenAI’s president who quit on Friday night; and Ilya Sutskever, a member of the company’s board.