[In the light of the current discussion on python-ideas regarding adding support for the Unicode minus sign]

I'm +1 on adding support for the minus code point, since
it's the correct correspondent to the plus code point in Unicode.
The traditional ASCII "-" is a compromise between a mathematical
minus and a hyphen.

https://en.wikipedia.org/wiki/Hyphen-minus

While we're at it, we should probably also include the
FULLWIDTH PLUS SIGN (U+FF0B) and SUPERSCRIPT PLUS SIGN (U+207A)
as alternative for the plus sign, and additionally the
SUPERSCRIPT MINUS (U+207B) as alternative for the minus
sign.

http://en.wikipedia.org/wiki/Minus_sign

I'm also +1 on adding support for other mathematical symbols used in parsing numbers, but only if their purpose is clearly defined in the Unicode database (i.e. accepting an "e" in some other script for exponential notation should not be allowed).