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The figures in this section illustrate some terms used to describe different parts of an

Gloss
Spacetrue
texpression
in the discussion of
Gloss
tnormal forms
, the guidance on
Gloss
Spacetrue
ttransforming expressions to normal forms
and on
Gloss
ttesting subsumption and equivalence between expressions
.

Anchor
_b7a9b061-d2c8-4027-8da2-17c143f1c154__a
_b7a9b061-d2c8-4027-8da2-17c143f1c154__a
Caption label
CapIdconcept-refinement
CapTypeFigure
Focus concepts and refinements
As illustrated by
Caption reference
CapRefIdconcept-refinement
CapRefTypeFigure
, an
Gloss
Spacetrue
texpression
consists of one or more conceptIds plus optional
Gloss
trefinements
. The
Gloss
Spacetrue
trefinements
may include any number of attributes.
Gloss
Spacetrue
tAttributes
are expressed as name-value pairs and may apply independently or as part of a group.

The name part of the

Gloss
tattribute value pair
 is a conceptId that refers to a
Gloss
Spacetrue
tconcept
that names the characteristic that is refined by this attribute. The value part of the
Gloss
tattribute value pair
 is an
Gloss
texpression
. In simple cases, this is just a conceptId referring to a
Gloss
Spacetrue
tconcept
that represents the appropriate value for this attribute. However, it may also be a nested
Gloss
Spacetrue
texpression
as shown in .

Caption reference
CapRefIdexpression-nesting
CapRefTypeTable
 illustrates the potential for nesting of
Gloss
texpressions
 and the naming conventions applied in this guide to distinguish different parts of an
Gloss
Spacetrue
texpression
at different levels. The top level of an
Gloss
Spacetrue
texpression
 is referred to as the "focus expression". It consists of a set of one or more
Gloss
tfocus concepts
 and a
Gloss
trefinement
. The values of the attributes in the
Gloss
tfocus concept
 
Gloss
Spacetrue
trefinement
are a "nested expression" that consist of one or more "value concepts" optionally refined by a nested
Gloss
trefinement
.
Gloss
Spacetrue
tExpressions
may be nested recursively so there may be further levels of "nested expressions" with "nested refinement". If it is necessary to distinguish the level of nesting, the following naming convention is applied.
Caption label
CapIdexpression-nesting-
CapTypeTable
Expression Nesting 

Level number

 

Gloss
tDescription
 

level 0

Gloss
texpression

Focus

Gloss
texpression

level 1

Gloss
texpression

Nested

Gloss
texpression

levelN

Gloss
texpression

An

Gloss
Spacetrue
texpression
nested inside a level ( N - 1)
Gloss
texpression

 

Caption label
CapIdnested-expression
CapTypeFigure
Illustration of the names used to refer to parts of a nested expression
The general pattern shown in
Caption reference
CapRefIdnested-expression
CapRefTypeFigure
 applies to all
Gloss
Spacetrue
texpressions
whether or not they include
Gloss
Spacetrue
tcontext
 information.
Caption reference
CapRefIdcontext-expression
CapRefTypeFigure
 illustrates the specific features of an
Gloss
Spacetrue
texpression
that includes a representation of
Gloss
tcontext
.

The "focus expression" of a context containing

Gloss
Spacetrue
texpression
is the
Gloss
tcontext wrapper
 and may include a "context refinement" consisting of a set of context attributes:

  • Concept
    t246090004|associated finding|
    ShowFormatinline
    or
    Concept
    t363589002|associated procedure|
    ;

  • Concept
    t408729009|finding context|
    ShowFormatinline
    or
    Concept
    t408730004|procedure context|
    ;

  • Concept
    t408732007|Subject relationship context (attribute)|
    ;

  • Concept
    t408731000|temporal context|
    .

In a normalized context

Gloss
texpression
, all context attributes are grouped. Each group in a normalized
Gloss
Spacetrue
tcontext wrapper
contains a complete set of four context attributes
Anchor
fnsrc_1
fnsrc_1
[1 .

The value of the

Concept
t246090004|associated finding|
ShowFormatinline
or
Concept
t363589002|associated procedure|
ShowFormatinline
is a "nested expression" which is referred to as the "clinical kernel".

During some stages of processing, the "clinical kernel" is separated from the "nested expression". When separated from its context the "clinical kernel" is the "focus expression" of a context-free

Gloss
texpression
.

 

Caption label
CapIdcontext-expression
CapTypeFigure
Illustration of the names used to refer to parts of an expression that represent context