[jjaksic]

But "shortening other summaries from its training set" is not all an LLM is capable off. It can easily shorten/summarize a text it had never seen before, in a way that makes sense. Sure, it won't always summarize it the same way a human would, but if you do a double blind test where you ask people whether a summary was written by AI, a vast majority wouldn't be able to tell the difference (again this is with a completely novel text).