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Also known as: Symmetry
A property where if A relates to B, then B relates to A.
DESCRIPTION
Symmetric properties model bidirectional relationships like sibling-of or married-to. Declaring symmetry ensures reverse links are logically inferred. In OWL, SymmetricObjectProperty marks such relations, simplifying data entry and reasoning. Overusing symmetry may create unintended cycles or dense graphs. Distinguish symmetry from antisymmetry and asymmetry in formal modeling.
ALTERNATIVE DEFINITIONS
W3C
A property is symmetric if whenever it relates x to y, it also relates y to x.
Direct, example-friendly definition of symmetry in OWL.
W3C
SymmetricObjectProperty(P) states that property P is symmetric.
Formal OWL axiom declaration for symmetric properties.
Wolfram MathWorld
A relation R is symmetric if xRy implies yRx.
Mathematical form defining symmetry using relational notation.
RELATED TERMS
Transitive Property Reflexive Property Inverse Property Equivalence Relation Reasoner OWL Binary Relation Property Characteristic
COMPETING TERMS
Asymmetric Property Antisymmetric Relation
KNOWLEDGE AREAS
Semantic & Knowledge Modeling Mathematics Data Modeling
TARGET AUDIENCE
Data Modeler Data Architect Information Analyst AI Engineer
EXTERNAL SOURCES
- Wikipedia - Symmetric relation
- W3C - Primer: symmetric properties
- Apache Jena - Symmetric property support
TOP QUESTIONS
When is a property Symmetric?
When a relation implies its reverse, such as married-to or equals.
Category: Definition
How do symmetric properties improve modeling?
They eliminate redundant reverse assertions by allowing reasoners to infer them.
Category: Impact
What is a mistake with Symmetric Property?
Applying symmetry to directional relations like parent-of creates logical errors.
Category: Mistakes
How to declare a Symmetric Property in OWL?
Mark the object property with SymmetricObjectProperty and validate with a reasoner.
Category: HowTo
How does symmetry differ from antisymmetry?
Antisymmetry allows xRy and yRx only when x=y; symmetry allows for distinct pairs.
Category: Comparison
Does symmetry imply transitivity?
No; they are independent characteristics and combining them may create dense graphs.
Category: Concept
What’s a real-world symmetric relation?
Is sibling-of is symmetric: if A is sibling of B, B is sibling of A.
Category: Example
Can data properties be symmetric?
OWL symmetry applies to object properties; data properties are typically values without symmetric semantics.
Category: Opinion
How to test symmetry?
Assert one direction, run the reasoner, and check inferred reverse links.
Category: HowTo