Substitute variables

Type

Selection

Range

The settings listed below

Default

Off

This option determines whether so called doubletons should be removed. Possible values are:

• Off

• On

A doubleton is defined by two variables that appear in a constraint of the form αX = αY, where X and Y are two variables and α is a value unequal to 0. If such a doubleton exists then Y can be replaced by X in all constraints, and variable Y and the constraint αX = αY can be deleted.

If this option is switched on then doubletons will be removed. However, if the variables X and Y of a doubleton appear together in any constraint other than the αX = αY constraint, then the doubleton will not be removed.