update general summary about identifiers

Author: gregsdennis

jsonschema-core.md

@@ -894,11 +894,11 @@ by other parties.
 
 ### Base IRI, Anchors, and Dereferencing
 
-To differentiate between schemas in a vast ecosystem, schemas are identified by
-[absolute IRIs](#rfc3987) (without fragments) and can embed references to other
-schemas by specifying their respective IRIs. When comparing IRIs for the
-purposes of resource identification, implementations SHOULD first follow the IRI
-normalization procedures defined in [RFC 3987](#rfc3987), section 5.3.
+To differentiate between schemas in a vast ecosystem, schema resources are
+identified by [absolute IRIs](#rfc3987) (without fragments).  These identifiers
+are used to created references between schema resources. When comparing IRIs for
+the purposes of resource identification, implementations SHOULD first follow the
+IRI normalization procedures defined in [RFC 3987](#rfc3987), section 5.3.
 
 Several keywords can accept a relative [IRI reference](#rfc3987), or a value
 used to construct a relative IRI reference. For these keywords, it is necessary