How do you force LaTeX to treat three closing quotation marks as the first one being a single-mark, the last two being a double mark?
This is important when a quote within a quote ends as follows:
``the cat 'sat on the mat'''.
This renders:
'' '.
But I want it to render:
' ''.
MWE:
\documentclass[11pt, a4paper]{book}
\begin{document}
``Testing `one, two, three'''.
\end{document}



{}does not inhibit ligatures, so your second alternative doesn't work there. You can fix that with a zero length space, instead:…three'\kern0pt''. This has the added advantage that adjusting the amount of space is trivial. (But of course, with luatex, you can just use the proper quotes directly, avoiding the whole issue.) – Harald Hanche-Olsen Nov 13 '17 at 14:33\,for the space. – barbara beeton Nov 13 '17 at 15:46\,is also recommended in Leslie Lamport's LaTeX: A Document Preparation System – Au101 Nov 14 '17 at 00:12