Next: Transition Rules: Semantics Up: Importing New Elements Previous: The Import Constructor

Auxiliary Vocabularies

The names of variables are different from function names of course, but it is convenient to treat free variables of rules as auxiliary nullary functions (which cannot be subjects of update instructions). An auxiliary vocabulary has the form Upsilon union V, where [Upsilon] is a genuine vocabulary and V is a finite set of variables.

If S is a state of an auxiliary vocabulary Upsilon'' = Upsilon union V, then Fun(S) = Upsilon'. S is appropriate for a rule R if [Upsilon] contains all function names of R and V contains all free variables of R . R is S -perspicuous if it is perspicuous and its bound variables do not occur in V .


huggins@acm.org
Thu Mar 23 17:30:35 EST 1995