### 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 -.