Uwe & Julien, thanks for your replies. I understand you are both referring to the option "Automatic inline completion", which indeed works as you describe.
I was referring to the third option in group "In Math" that says "Autocorrection". When that is checked, in math mode, the only visible change is that the status line says "Autocorrect off (! to enter)". If I type "!" the status line changes to "Autocorrect on (<space> to exit)". Other than these messages in the status line, nothing seems to happen, or I don't know what to do. (By the way, the status line message for some reason appears not immediately but only after typing something in math mode.) This is LyX Version 2.0.0 on Ubuntu Linux. Regards. --JH
