BFO 2 Reference: object aggregates may gain and lose parts while remaining numerically identical (one and the same individual) over time. This holds both for aggregates whose membership is determined naturally (the aggregate of cells in your body) and aggregates determined by fiat (a baseball team, a congressional committee).

An entity a is an object aggregate if and only if there is a mutually exhaustive and pairwise disjoint partition of a into objects

(forall (x) (if (ObjectAggregate x) (and (MaterialEntity x) (forall (t) (if (existsAt x t) (exists (y z) (and (Object y) (Object z) (memberPartOfAt y x t) (memberPartOfAt z x t) (not (= y z)))))) (not (exists (w t_1) (and (memberPartOfAt w x t_1) (not (Object w)))))))) // axiom label in BFO2 CLIF: [025-004]

ISBN:978-3-938793-98-5pp124-158#Thomas Bittner and Barry Smith, 'A Theory of Granular Partitions', in K. Munn and B. Smith (eds.), Applied Ontology: An Introduction, Frankfurt/Lancaster: ontos, 2008, 125-158.

a symphony orchestra

defined through physical containment: the aggregate of molecules of carbon dioxide in a sealed container

the nitrogen atoms in the atmosphere

the aggregate of bearings in a constant velocity axle joint

defined through physical attachment: the aggregate of atoms in a lump of granite

defined by fiat: the aggregate of members of an organization

a collection of cells in a blood biobank.

the restaurants in Palo Alto

an organization is an aggregate whose member parts have roles of specific types (for example in a jazz band, a chess club, a football team)

a swarm of bees is an aggregate of members who are linked together through natural bonds

defined via attributive delimitations such as: the patients in this hospital

the aggregate of blood cells in your body

your collection of Meissen ceramic plates.

b is an object aggregate means: b is a material entity consisting exactly of a plurality of objects as member_parts at all times at which b exists. (axiom label in BFO2 Reference: [025-004])

ObjectAggregate

object-aggregate

object aggregate