On my old computer, sadly defunct, there was a program for doing accented letters. Unfortunately I have lost its name and am hoping some Doper knows what it is.
The way it worked was every character you wanted started by hitting—and releasing the right alternate key. If you then hit, say '+e you got an acute e. `+e got you a grave e, "+o got an umlauted o. IIRC correctly H+o got you the accent you need for Erdos. (Of course the + signs are not to be typed.)
It is not the stupid Microsoft program where rt.alt+e gives an acute e but there is no way to get the grave accent. If some Doper can remind me what the name was so I can install it on my replacement computer, I would be very grateful.
I only know the Mac stuff. There’s probably brilliant Windows stuff out there, I’m just ignorant of it because I only use Windows as a second language. For us Mac folks, Keyboard Preferences lets you put an icon in your menu bar and you can invoke a virtual keyboard at any time; our way of invoking special characters (∂ƒé∆¢flß etc) is to hold down the option key (shift key gives you an additional set when joined with the option key), and the virtual keyboard displays what you’d get if you did that keystroke. Or you can click on the virtual keyboard itself to input the symbol that you want.
Doesn’t have every symbol in existence. Some symbols have to be inserted with more arcane processes.