Meta Properties

Formulas

A formula is an expression that combines logical operators and properties. The value of a formula is expressing in a trivalued logic. A formula can be certainly true, certainly false or unknown.

with op in {not}

op <ppt>

with op in {and, or, xor}

<ppt1> op <ppt2>

Conditional properties

A conditional property allow the user to post properties considering the logical value of a formula.

• IfThen: The properties enclosed in the <ListOfProperties> are posted if and only if the <LogicalFormula> is certainly true. Otherwise … nothing is posted.

IfThen (  <LogicalFormula>  , <ListOfProperties> );

• IfThenElse: The properties enclosed in the <ListOfProperties> are posted if and only if the <LogicalFormula> is certainly true. The properties enclosed in the <OtherListOfProperties> are posted if and only if the <LogicalFormula> is certainly false. Otherwise … nothing is posted.

IfThenElse( <LogicalFormula> , <ListOfProperties> , <OtherListOfProperties> );

Set of properties

A set of properties is considered as a block of properties.

{
<ppt1> ;
<ppt2> ;
...
<pptn> ;
}

Example

Model MetaEx()
Constants

Variables
x : Real in [0, +maxreal];
z : Integer;

Elements

Properties
IfThenElse((x > 3) and (z < 20),
         [x^2 = 16,
         x + z = 15
         ],
         [x^2 = 1,
         x + z = 10
         ]);
End