Typesetting of negative versus minus?

If latex gives you a binary minus and you want the unary minus (i.e. negative), just add curly braces around the expression, e.g. change -x to {-x}. See post #4 at mathhelpforum

My understanding is that a negative sign is the same as a minus sign, but the spacing is different since it's a unary operator rather than a binary operator. You can see this in TeX: $-x$ has different spacing from $y-x$:

I'm not sure I can answer your question about it being proper, but I'll say that I've never seen mathematics typeset with a raised, smaller negative sign. (But take that with a grain of salt because most, but not all, math I read is typeset with LaTeX.)

Here is an example, but you still have to distinguish between unary and binary minus manually:

\documentclass{minimal}

\usepackage{xparse}

\makeatletter
\NewDocumentCommand{\raisedminus}{m}{%
  \raisebox{0.2em}{$\m@th#1{-}$}%
}
\NewDocumentCommand{\unaryminus}{}{%
  \mathbin{%
    \mathchoice{%
      \raisedminus\scriptstyle
    }{%
      \raisedminus\scriptstyle
    }{%
      \raisedminus\scriptscriptstyle
    }{%
      \raisedminus\scriptscriptstyle
    }%
  }%
}
\makeatother

\begin{document}

$\unaryminus 3 - 4$

\end{document}