has member part at some time [copied from inverse property 'member part of at some time'] each piece in a chess set is a member part of the chess set; each Beatle in the collection called The Beatles is a member part of The Beatles. [copied from inverse property 'member part of at some time'] each tree in a forest is a member_part of the forest [copied from inverse property 'member part of at some time'] b member_part_of c at t =Def. b is an object & there is at t a mutually exhaustive and pairwise disjoint partition of c into objects x1, …, xn (for some n > 1) with b = xi for some 1 ? i ? n. (axiom label in BFO2 Reference: [026-004]) [copied from inverse property 'member part of at some time'] Alan Ruttenberg: This is a binary version of a ternary time-indexed, instance level, relation. The BFO reading of the binary relation 'member part of at some time@en' is: exists t, exists_at(x,t) & exists_at(y,t) & 'member part of@en'(x,y,t) [copied from inverse property 'member part of at some time'] BFO2 Reference: object aggregate has-member-part_st [copied from inverse property 'member part of at some time'] BFO2 Reference: object member part of at some time has continuant part at some time continuant