Latex sequence \/?

Question

This is probably very simple but I couldn't find anything about in the usual latex guides. In this phrase:

{\em hello\/}

what is the purpose of the "\/" ?

Answer 1

This is a so-called italic correction. Its purpose is to ensure proper spacing after italic text.

Example:

• {\itshape M}M produces MM, but italics M touches normal M.
• {\itshape M\/}M produces M M, with a bit more spacing to avoid touching.

Answer 2

\/ is also the standard macro for separating letters which would otherwise form a ligature, so as said before it acts as a separator. But if you’re using the packages german/ngerman (deprecated), or babel with option german/ngerman (I don’t know at the moment whether it works on other languages as well) you can take "| which generates slightly better spacing and does not influence the hyphenation, as \/ would.