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A

Gloss
Spacetrue
tconcept
definition has one of the following two forms:

  1. Sufficiently Defined

    Glossary include
    Glosssufficiently defined concept
    Suffix is defined as
    Definline
    Exampletrue
    Notetrue
    Prefix A

    •  The value of  If a concept has sufficient definition is that it allows a postcoordinated , it is possible to infer whether another concept or a 

      Gloss
      Spacetrue
      tpostcoordinated expression
      that is sufficient to define a  is a 
      Gloss
      Spacetrue
      tconcept
      to be recognized as equivalent to (or a
      subtype
       of, or equivalent to, that
      Gloss
      Spacetrue
      tsubtype
      of) a defined
      Gloss
      tconcept.


  2. Primitive

    Glossary include
    Glossprimitive concept
    Suffix is

    defined as

    Definline
    Exampletrue
    Notetrue
    Prefix A

Necessary Conditions

All SNOMED CT defining relationships currently released are necessarily (always) true for the concept defined. Relationships that are necessarily true are also know as necessary conditions.

...

but this is not currently represented in SNOMED CT. The reason for this is that that currently the currently the profile of description logic used by SNOMED CT does not support representation of multiple sufficient sets. 

When multiple sufficient sets are supported, satisfying a single sufficient set enables an inference to be made that all necessary conditions must also be true. For example

 

  • The definition

    Concept
    t363698007|finding site|
    =
    Concept
    t78653002|gastric mucosa|
    ShowFormatinline
    is a necessary condition for
    Concept
    t397825006|gastric ulcer|
    :

    • This is true because all gastric ulcers necessarily involve the

      Concept
      t78653002|gastric mucosa|

  • The definition

    Concept
    t116676008|morphology|
    =
    Concept
    t56208002|ulcer|
    ShowFormatinline
    and
    Concept
    t363698007|finding site|
    =
    Concept
    t69695003|stomach structure|
    ShowFormatinline
    is a sufficient definition for
    Concept
    t397825006|gastric ulcer|
    :

    • This is true because any ulcer in a stomach structure is a

      Concept
      t397825006|gastric ulcer|

  • Therefore, an assertion that a person has an

    Concept
    t56208002|ulcer|
    ShowFormatinline
    with
    Concept
    t363698007|finding site|
    ShowFormatinline
    Concept
    t69695003|stomach|
    ShowFormatinline
    is sufficient to imply that they have a
    Concept
    t397825006|gastric ulcer|
    :

    • Since a gastric ulcer necessarily involves the

      Concept
      t78653002|gastric mucosa|
      ShowFormatinline
      it should be possible to deduce that a person with an "ulcer" with finding site
      Concept
      t69695003|stomach|
      ShowFormatinline
      has a disorder of with a site
      Concept
      t78653002|gastric mucosa|

...