Chapter 4. Definitions

For the purposes of this document, the following definitions, as specified in the ISO/IEC Directives, Part 2, 2001, 4th Edition, apply:


be able to; there is a possibility of; it is possible to


be unable to; there is no possibilty of; it is not possible to


is permitted; is allowed; is permissible

need not

it is not required that; required


is to; is required to; it is required that; has to; permitted; it is necessary

shall not

is not allowed [permitted] [acceptable] [permissible]; is required to be not; is required not; is not to be


it is recommended that; ought to

should not

it is not recommended that; ought not to