This was complex. The acquired company was in the US, but not in CA. The university was in Australia, and yes they also claimed ownership (which had already been agreed as part of starting the PhD). It's quite likely the work on the PhD prior to the Oracle acquisition was done on the original acquired companies equipment (and probably time as well).

It was without doubt a time wasting and frustrating shitfight ensuring he was "allowed" to think about his PhD topic after being acquired by Oracle (although he had enough equity to have done quite nicely out of the deal anyway, I suspect...)