This section briefly outlines different aspects of assertions made about concepts and the extent to which they are necessarily true or form part of a sufficient definition of the concept. More detailed illustrations of some of the points on this page are provided in D.2 Necessary and Sufficient  Examples.
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AssertionsThe of consists of one or more assertions made by . Necessary ConditionsEach time an assertion is made about a concept, an must decide if that assertion is a . If the assertion is always true for that concept and its , it is a . This implies that for all instances of that concept or its subtypes, the assertion must be true, even if it has not been explicitly stated.
Glossary include 

Gloss  necessary condition 

Suffix  is defined as 

Def  inline 

Example  true 

Prefix  A 


Sufficient DefinitionsFor each an must decide if there are one or more sets of assertions that form a of that concept. A set of assertions is a if it distinguishes a and its subtypes from other concepts.  This implies that if all assertions in the set are true for a concept, it must be an instance of the defined concept or a subtype of that concept.
Glossary include 

Gloss  sufficient definition 

Suffix  is 

Def  inline 

Example  true 

Note  true 

Prefix  A 


Concepts with no Sufficient DefinitionsA that has no is a . Because have no it is not possible for a Gloss 

t  description logic classifier 

 to determine if other concepts are of this concept. Similarly, it is not possible to automatically determine whether an expression is a subtype of a primitive concept. Therefore, only concepts or expressions that explicitly state they are subtypes of primitive concepts will be treated as subtypes when applying expression constraints or undertaking analysis. However, note that this does not prevent a being classified as a subtype of a Gloss 

t  sufficiently defined concept 

 . Concepts with a Sufficient DefinitionA that has at least one is a Gloss 

t  sufficiently defined concept 

 . A Gloss 

t  description logic classifier 

 can determine whether the stated definitions of other concepts meet at least one of the and if so will classify these concepts as its . Similarly, it is possible to determine whether an expression is equivalent to or a subtype of a Gloss 

t  sufficiently defined concept 

 . Therefore, where expression constraints or queries refer to Gloss 

t  sufficiently defined concepts 

 the results will include the inferred subtypes of these concepts.Sufficiently Defined Concepts with Necessary ConditionsIf a Gloss 

t  sufficiently defined concept 

 has one or more additional then any concept or expression that satisfies one of its will also inherit any .For example one sufficient definition of Concept 

t  397825006 Gastric ulcer (disorder) 

 is an ulcer in a stomach structure: Scg expression 

=== 64572001 disease : { 116676008 associated morphology = 56208002 ulcer ,
363698007 finding site = 69695003 stomach structure } 
However, another definition could be created with a more specific site gastric mucosa: Scg expression 

=== 64572001 disease: { 116676008 associated morphology = 56208002 ulcer ,
363698007 finding site = 78653002gastric mucosa } 
In both cases these definition are equivalent to Concept 

t  397825006 Gastric ulcer (disorder) 

 . The more general definition is flexible when it comes to allowing refinement to a specific location of the ulcer within the stomach, which is actually useful information. It also avoids requiring an expression to refer specifically to the mucosa (stomach lining), which is where all gastric ulcers occur.For example, an expression including the specific location could look like this Scg expression 

=== 64572001 disease : { 116676008 associated morphology = 56208002 ulcer ,
363698007 finding site = 127869006 Anterior wall of fundus of stomach } 
This satisfies the sufficient definition because the finding site is a subtype of stomach structure. This will therefore classify as a type of Concept 

t  397825006 Gastric ulcer (disorder) 

 located in the anterior wall of the gastric fundus. The problem is that a query for disorders of the gastric mucosa will not find this expression. Scg expression 

<< 64572001 disease: 363698007 finding site = 78653002gastric mucosa 
However, adding the definition that refers to the gastric mucosa as an additional can solve this problem. The expression satisfies the implying this is a type of Concept 

t  397825006 Gastric ulcer (disorder) 

 . The fact that it is a type of gastric ulcer causes it to inherit Concept 

t  363698007 finding site = 78653002gastric mucosa 

 so it will now be included in the query for disease in the gastric mucosa. 