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The appendix contains an extended version of  2.3.1 Stated and Inferred Concept Definitions supported by more detailed examples.

Stated View of Concept Definitions

SNOMED CT concepts are defined by assertions made by SNOMED CT authors. The concept definitions asserted by SNOMED CT authors are known as the stated view.

The stated view is a representation of concept definitions consisting only of assertions made or revised by SNOMED CT authors.

Notes

Description Logic Classification

A description logic classifier can apply logical rules to the stated view to create inferences. The end result of this process is an inferred view of concept definitions.

Inferred Views of Concept Definitions

The inferred view is a representation of concept definitions that is logically derived by applying a description logic classifier to the stated view.

Notes

  • Different inferred views can be derived from the same stated view by applying different rules that selectively exclude some types of assertions. 
  • Different inferred views may be semantically equivalent to one another provided that assertions are only excluded if they are redundant (i.e. can be inferred  from assertions that are included). However, in some cases, an inferred view may not completely represent the concept definition but may serve a specific purpose.

Illustration of the Effect of Classification

Table D.1-1 shows the stated view of the definitions of  710785000 | Laparoscopic repair of hernia| . Compare this with the  inferred view of the same concept in  Table D.1-2 and you can see that the single supertype concept  71388002 | Procedure|  been replaced by four supertype concepts in the  inferred view.

The classifier has compared the definition of  710785000 | Laparoscopic repair of hernia|  with the concept definitions shown in  Table D.1-3 and determined that  710785000 | Laparoscopic repair of hernia|  is a subtype of all these concepts.

In fact, the classifier will also have found several other supertypes but the inferred view distributed in the  relationship file only includes proximal supertypes (parents). Other supertype ancestors are excluded from the file because they are redundant 1 .

Table D.1-1: Stated view of the definition of |Laparoscopic repair of hernia|

ConceptStated View of Concept Definition

710785000 | Laparoscopic repair of hernia|

Table D.1-2: Inferred view of the definition of the concept |Laparoscopic repair of hernia|

ConceptInferred View of Concept Definition

710785000 | Laparoscopic repair of hernia|

Table D.1-3: Stated views of the four supertype concepts in the inferred |Laparoscopic repair of hernia|

ConceptStated View of Concept Definition

363321000 | Surgical repair procedure by device|

===  4365001 |Surgical repair|  :
            {  405815000 |Procedure device|  =  49062001 |Device| , 
               260686004 |Method|  =  257903006 |Repair - action|  }

50465008 | Hernia repair|


4365001 | Surgical repair|

A supertype in the two definitions above

51316009 | Laparoscopic procedure|


363687006 | Endoscopic procedure|

A supertype in the definition above

===  71388002 |Procedure|  :
            {  425391005 |Using access device|  =  37270008 |Endoscope, device| , 
               260686004 |Method|  =  129284003 |Surgical action|  }

264274002 | Endoscopic operation|

===  71388002 |Procedure|  :
            {  425391005 |Using access device|  =  37270008 |Endoscope, device| , 
               260686004 |Method|  =  129284003 |Surgical action|  }


Footnotes
Ref Notes
1 Supertype ancestor relationships are not included in the inferred view distributed in the relationship file because they do not contribute directly to the concept definition and can be reached transitively.

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