In order to keep the Design Constraints more clear and simple, here are some guidelines for terminology. These terms may move to the glossary when/if they become more stable.

- RIF Core
- The extensible format specified during Phase 1, suitable by iself for interchanging Horn rules. Constraints on RIF Core concern the Phase 1 work.
- Standard RIF
- RIF Core extended with some set of extensions approved as Recommendations by the W3C. Constraints on "Standard RIF" concern work in either Phase 2 or by later Working Groups.
- Extended RIF
- RIF Core extended with some set of extensions not approved as Recommendations by the W3C. Constraints on "Extended RIF" are indirectly constraints on "RIF Core" and thus concern Phase 1 work.
- RIF
- an ambiguous term usually meaning either "Standard RIF" or "Extended RIF" (or, of course, the Rule Interchange Format Working Group itself!)
- RIF Dialect
- The language/format formed when combining RIF Core with a particular set of extensions
- Cover
A

**ruleset**is covered by a RIF Dialect if that dialect can be used to faithfully convey that ruleset. (Exactly what it means to "faithfully convey" the ruleset still needs to be refined.) A**language**is covered by a RIF Dialect if and only if all rulesets which can be written in that language are covered.-

*Example:*"Extended RIF must cover full first-order logic" is short for "it must be possible to specify an extension to RIF Core, such that RIF-Core-plus-this-extension forms a language in which one can write all the well-formed formulas of full first-order logic."