In another submission, Yann Lecun says they did not sign this letter.

https://news.ycombinator.com/item?id=35353484

and in a reply to that tweet, someone points out that "Xi Jinping" had also signed the letter.

So it seems that the supposed signatories are not verifiable and many of them might be faked.

The Reuters editors seem to have done not even a basic verification on this story.

Sure sure.

While the same groups will keep on developing it but behind closed doors.

Perhaps naive question, but how do you decide if an AI system is "more powerful" than GPT-4? In particular what happens if your AI isn't a language model? How do you compare the "power" of a non-language AI to GPT-4?

I am urging my competition to please stop what they're doing while I catch up.

Yes yes. Let us catch up please.