UNARY--.html -- ACL2 Version 6.3

### UNARY--

arithmetic negation function

    Major Section:  ACL2-BUILT-INS

Completion Axiom (`completion-of-unary-minus`):

    (equal (unary-- x)
           (if (acl2-numberp x)
               (unary-- x)
             0))

Guard for `(unary-- x)`:

    (acl2-numberp x)

Notice that like all arithmetic functions, `unary--` treats non-numeric inputs as `0`.

Calls of the macro `-` on one argument expand to calls of `unary--`; see -.