BFO-Core
Classes
Entity
Entity
The class entity is comprised of all instances within the scope of BFO, that is, those instances researched and used by the empirical sciences. entity is bifurcated into two disjoint subclasses: continuant and occurrent.
graph TD
A(Entity):::BFO --> B(Continuant):::BFO
A(Entity):::BFO --> O(Occurrent):::BFO
classDef BFO fill:#4b0082,color:#FFFFFF
Continuant
graph TD
A(Continuant):::BFO --> B(Independent Continuant):::BFO
A(Continuant):::BFO --> O(Specifically Dependent Continuant):::BFO
A(Continuant):::BFO --> G(Generically Dependent Continuant):::BFO
classDef BFO fill:#4b0082,color:#FFFFFF
Starting at the continuant side of the BFO hierarchy, an independent continuant is distinguished from other continuants in that they neither generically nor specifically depend on other entities. In contrast, a specifically dependent continuant specifically depends on an independent continuant8 rigidly. If x specifically depends on y, then as long as x exists, the relation holds. If y ceases to exist, then x does as well.
graph TD
H(Immaterial
Entity):::BFO --> P(Spatial
Region):::BFO
P(Spatial
Region):::BFO --> U(One-Dimensional
Spatial Region):::BFO
P(Spatial
Region):::BFO --> V(Two-Dimensional
Spatial Region):::BFO
P(Spatial
Region):::BFO --> W(Three-Dimensional
Spatial Region):::BFO
classDef BFO fill:#4b0082,color:#FFFFFF
graph TD
H(Immaterial
Entity):::BFO --> O(Site):::BFO
H(Immaterial
Entity):::BFO --> Q(Continuant Fiat
Boundary):::BFO
Q(Continuant Fiat
Boundary):::BFO --> R(Fiat
Point):::BFO
Q(Continuant Fiat
Boundary):::BFO --> S(Fiat
Surface):::BFO
Q(Continuant Fiat
Boundary):::BFO --> T(Fiat
Line):::BFO
classDef BFO fill:#4b0082,color:#FFFFFF
A specifically dependent continuant is said to inhere in – a relation defined in terms of specifically depends on – an instance of independent continuant. The inverse of inheres in is bearer of. A generically dependent continuant is concretized by a process or specifically dependent continuant. When the concretization is a specifically dependent continuant the generically dependent continuant generically depends on the specifically dependent continuant’s bearer.
graph TD
D(Specifically Dependent
Continuant):::BFO --> I(Quality):::BFO
D(Specifically Dependent
Continuant):::BFO --> J(Realizable
Entity):::BFO
I(Quality):::BFO --> K(Relational
Quality):::BFO
J(Realizable
Entity):::BFO --> L(Role):::BFO
J(Realizable
Entity):::BFO --> M(Disposition):::BFO
M(Disposition):::BFO --> N(Function):::BFO
classDef BFO fill:#4b0082,color:#FFFFFF
All independent continuants other than spatial regions occupy a spatial region, and so are extended in space and time. Some may be located in others at some time, as the food you ingest is at some point located in the lumen of your stomach after you have eaten. Located in is transitive.
graph TD
G(Material
Entity):::BFO --> X(Fiat Object Part):::BFO
G(Material
Entity):::BFO --> Y(Object
Aggregate):::BFO
G(Material
Entity):::BFO --> Z(Object):::BFO
classDef BFO fill:#4b0082,color:#FFFFFF
A material entity can be continuant part of another material entity at some time. Material entities can have material and immaterial parts. An object can be member part of an object aggregate. Member part of is not transitive but implies continuant part of. An object aggregate always has at least one member, and must, at some time, have more than one.
Occurrent
graph TD
C(Occurrent):::BFO --> AA(Process):::BFO
C(Occurrent):::BFO --> AB(Process
Boundary):::BFO
C(Occurrent):::BFO --> AC(Temporal
Region):::BFO
C(Occurrent):::BFO --> AD(Spatiotemporal
Region):::BFO
AA(Process):::BFO --> AE(History):::BFO
AC(Temporal
Region):::BFO --> AF(Zero-Dimensional
Temporal Region):::BFO
AC(Temporal
Region):::BFO --> AI(One-Dimensional
Temporal Region):::BFO
AF(Zero-Dimensional
Temporal Region):::BFO --> AG(Temporal
Instant):::BFO
AI(One-Dimensional
Temporal Region):::BFO --> AH(Temporal
Interval):::BFO
classDef BFO fill:#4b0082,color:#FFFFFF
Any independent continuant, specifically dependent continuant, or generically dependent continuant can participate in a process. In the latter two cases, it is implied that their bearer also participates in the process. When a process realizes a realizable entity, the realizable entity’s bearer also participates in the process. When a generically dependent continuant participates in a process p, some concretization of the generically dependent continuant participates in p. If that concretization is a process, it is temporal part of p.
A process occupies temporal region some temporal region. Processes have at least one process boundary as part. The temporal region that a process occupies must have as part a temporal interval. A process boundary can only occupy a temporal instant. An occurrent can be a temporal part of some other. Occurrent parts can differ from what they are part of both spatially and temporally (e.g. the process which occurs in the left half of a soccer field during the first period of a game). By contrast, temporal part of an occurrent differs in that there is no difference in the spatial extent of the part and the whole.
Temporal regions provide the indices for all the time-indexed ternary relations in BFO. A temporal region has first instant and has last instant a temporal instant marking its extrema. A first or last instant can be temporal part of the region or not. A temporal instant that precedes the last instant of a temporal interval and are preceded by the interval’s first instant are necessarily part of the interval. Using these relations, the familiar and widely used Allen’s interval algebra may be formulated.
Relations
Mereology
BFO’s theory of parts is modeled after Minimal Extension Mereology (MEM). MEM is described in terms of binary part relations, but is extended to handle the time-indexed relations. The MEM axioms state that a part relation is reflexive, antisymmetric, transitive, weakly supplemented, and exhibits the unique product property. Any time-indexed relation implies that the first two relata exist, and holds at any time the relata exist. For instance, when a timeindexed relation is reflexive we mean that the self-relationship refers to the first two relata and it must hold at any time the relata exist.
BFO has two part of relations, one for continuants, called continuant part of and one for occurrents called occurrent part of. Continuant part of is time indexed, whereas occurrent part of is not. Worth noting is the treatment of the anti-symmetry of continuant part of applied to object aggregates. If a continuant part of b at some t and b continuant part of a at the same time t, we do not conclude that a=b.
Using these relations we can define irreflexive, asymmetric, transitive proper occurrent part of and proper continuant part of relations in the usual way.