@tie{}: Inserting an Unbreakable SpaceThe @tie{} command produces a normal interword space at which
a line break may not occur.  Always write it with following (empty)
braces, as usual for commands used within a paragraph.  Here's an
example:
     @TeX{} was written by Donald E.@tie{}Knuth.
     
produces:
     TeX was written by Donald E. Knuth.
     
  There are two important differences between @tie{} and
@w{ }:
     
@tie{} will stretch and shrink slightly
along with the normal interword spaces in the paragraph; the space
produced by @w{ } will not vary.
     @tie{} allows hyphenation of the surrounding words, while
@w{ } inhibits hyphenation of those words (for TeXnical
reasons, namely that it produces an \hbox).