Fix UML property multiplicity terminology

Closes #39

Signed-off-by: Johannes Echterhoff <[email protected]>

requirements/core/REQ013.adoc

@@ -5,16 +5,16 @@ identifier:: http://www.opengis.net/spec/uml2json/1.0/req/core/property-multipli
 
 [.component,class=part]
 --
-If the minimum cardinality of a UML property is 1 or greater, and the class that owns the property is not a «union», then the property shall be listed under the "required" properties of the JSON object to which the property belongs.
+If the multiplicity lower bound of a UML property is 1 or greater, and the class that owns the property is not a «union», then the property shall be listed under the "required" properties of the JSON object to which the property belongs.
 --
 
 [.component,class=part]
 --
-In addition, if the maximum cardinality of the property is greater than 1, then the JSON Schema definition for the property shall be created as follows.
+In addition, if the multiplicity upper  bound of the property is greater than 1, then the JSON Schema definition for the property shall be created as follows.
 
 * The "type" of the JSON property is set to "array", with the "items" keyword containing the JSON Schema constraints that are created to represent the value type of the property.
-* If the minimum cardinality is greater than 0, it is encoded using the "minItems" keyword.
-* If the maximum cardinality is not unbounded, it is encoded using the "maxItems" keyword.
+* If the multiplicity lower bound is greater than 0, it is encoded using the "minItems" keyword.
+* If the multiplicity upper  bound is not unbounded, it is encoded using the "maxItems" keyword.
 * If the values of the property are defined to be unique (which is the default for UML properties), then that is represented by adding `"uniqueItems": true`.
 --
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