-y is the negative of y .That is, it is defined
as 0 - y .Thus, -2 0 _2 is _2 0 2 .
- is defined as in elementary arithmetic, and
is extended to complex numbers as usual.
The function-is self-inverse,
that is, -^:_1 is - itself.
Although -2 may often be used instead of _2,
it is important to understand that the former is the application of a
function to the number 2,whereas the symbol _
is an indivisible part of the number representation,
just as the period is an indivisible part of a number such as 8.9.