# What is `-` on bitvectors?

### Question

What is `-`

on bitvectors?

### Answer

The `-`

operator for bit-vectors is subtraction or unary negation.
Unary negation, `- b`

is equivalent to `0 - b`

.
This is not the same as complement, which is written as `! b`

.

For example, the `bv5`

value equivalent to the natural number `13`

is `01101`

.

- The complement of this value is
`10010`

, which is`18`

. - The negation of this value is
`10011`

, which is`19`

.

In 2’s complement fixed-bit-width arithmetic, `-x`

is `!x + 1`

.