@minus (−): Inserting a Minus Sign ¶Use the @minus{} command to generate a minus sign.
Where the character encoding and font used in the output allow it,
the symbol is the customary length for a minus sign—a little longer
than a hyphen, shorter than an em-dash:
‘−’ is a minus sign generated with ‘@minus{}’,
‘-’ is a hyphen generated with the character ‘-’,
‘—’ is an em-dash for text.
If you actually want to typeset some math that does a subtraction, it
is better to use @math, as in @math{a-b} (see @math and @displaymath: Formatting Mathematics).