Up Next
Go up to 2.3 Axioms
Go forward to 2.3.2 Logical Connectives

2.3.1 Quantifications

      QUANTIFICATION ::= quantification QUANTIFIER VAR-DECL+ FORMULA
      QUANTIFIER     ::= forall | exists | exists-uniquely

A quantification with the forall quantifier is written:

forall VD1; ...; VDn · F
The sign displayed as the `for all' symbol in LaTeX is input as `forall'. The sign displayed as ` · ' may be input as `·' in ISO Latin-1, or as `.' in ASCII.

A quantification with the exists quantifier is written:

exists VD1; ...;VDn · F

A quantification with the exists-uniquely quantifier is written:

exists! VD1; ...;VDn · F
The sign displayed as the `exists' symbol in LaTeX is input as `exists'.

The first case is universal quantification, holding when the body F holds for all values of the quantified variables; the second case is existential quantification, holding when the body F holds for [CHANGED:] some [] values of the quantified variables; and the last case is unique existential quantification, abbreviating a formula that holds when the body F holds for unique values of the quantified variables.

The formula forall VD1; ...; VDn · F is equivalent to forall VD1 · ...forall VDn · F; and forall V1, ..., Vn:s · F is equivalent to forall V1:s · ...forall Vn:s · F. Similarly for the other quantifiers. The scope of a variable declaration in a quantification is the component formula F, and an inner declaration for a variable with the same identifier as in an outer declaration overrides the outer declaration (regardless of whether the sorts of the variables are the same).


CoFI Document: CASL/Summary-v1.0 -- Version: 1.0 -- 22 October 1998.
Comments to cofi-language@brics.dk

Up Next