I can use
~ to produce a non-breaking space. But it is too large for me, and I would like a non-breaking space of the size of
\, for example. Is it possible ?
There are two kinds of spacing that TeX can use: skips and kerns. The first sort of space can be flexible (the interword space is a skip, for instance), while the second one is rigid.
Both disappear at line breaks, but TeX will never break a line at a kern (unless it's followed by a skip), while it's willing to do it at skips. Therefore
would never be broken across lines.
(where 1em is approximately the width of an uppercase "M", whence the name, or near the font size in points); so the space inserted by
(the last is "backslash+space"). There will be no line break at it, because the skip inserted by
You can space by inserting
would insert a space normally equal to 1/6 of an em, but stretchable to 1/4 of an em.
I left out the