Bindings and Orderings

Plan bindings (codesignation constraints) specify the relationships between variables and constants. The following relationships are possible:

• Two variables may codesignate;
• A variable may designate a constant;
• A variable may be constrained not to designate a constant;
• Two variables may constrained not to codesignate.

An ordering constrains the order of two steps with respect to each other, so that step S1 must precede step S2 (S1 < S2).