Object subsets may be formally defined by using the basic attributes recognised by **ORION**.
These attributes fall into 5 general types:

- attributes which are independent of the state of the model and of the existence of other
variables. They are:
ALLNAMES patternspec - FILTER patternspec factor

NAMes patternspec TYPe patternspec factor KIND patternspec factor - VARIABLE integerspec

- attributes which depend upon the variable being in a certain environment. They are:
LTOV factor - VTOL factor

- attributes which depend upon the variable being connected in some way to other
variable(s). The connection is usually dependent on the logical state of the connection.
Both synonyms and directed synonyms are traversed in checking for connection. The
connection attributes are:
ALTERNATIVES factor ALTERNATIVE_OF factor ATTRIBUTES factor ATTRIBUTE_OF factor - CHECKPARENTS factor

CHILDREN factor COMPONENTS factor - COMPONENT_OF factor

CONTAINS factor - CONTAIN_IN factor

DITRANSREL factor INVOCATIONS factor INVOCATION_OF factor LINKS factor - MEANINGS factor

- MEANING_OF factor

- MEMBERS factor

- MEMBER_OF factor

OBJECTREL factor - OCN - Connection to operator

- PARAMETERS factor

- PARENTS factor

- RECURSE factor

- RELATIONS factor

SUBJECTREL factor

- attributes dependent on the Current Solution state of the Model. They are:
BAYESVALue valuespec factor - EXISTVALue valuespec factor

INDIRECT factor RANGE valuespec factor - SIZE integerspec factor

STATe logicalspec factor - EXISTS existsspec factor

VALues valuespec factor The connection criteria, such as MEMBERS, also depend on the state of the model - if the logical control of the operator is set false, no notice is paid to the connection.

- attributes which allow the user to refer to the last selected set, or to cycle though a
set.
ARBitrary CURrent FND factor integerspec FOR factor factor IF factor factor NODE AND CONSISTENT HOWCONNECTED - finding a connection path between nodes MATCH MEANINGS2 OR - SEARCH

XOR

Any of the attributes may be combined into arbitrarily complex selection expressions by using the set combination operators - that is, AND, CONSISTENT, MINUS, OR, XOR.

See **Attributor**