Complex conditions

A complex condition is a negation, a conjunction or a disjunction of conditions.

• A negation is a condition that has one of the forms:

  ``NO'' condition

  ``NOT'' condition

  An example of negation is ``Not User identification is valid''.

  Notice that negation may also be introduced in the verb form as in ``Not User identification is not valid''. Both forms are equivalents.

• A conjunction/disjunction of a condition has one of the form:

  condition ``AND'' condition

  condition ``OR'' condition

  The default associativity of ``AND'' and ``OR'' is from the left to the right. Parentheses may be used to alter that order.