member part of at some time member-part-of_st memberPartOfAt BFO2 Reference: object BFO2 Reference: object aggregate (forall (x y t) (if (memberPartOfAt x y t) (continuantPartOfAt x y t))) // axiom label in BFO2 CLIF: [104-001] 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) 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]) 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. each tree in a forest is a member_part of the forest if b member_part_of c at t then b continuant_part_of c at t. (axiom label in BFO2 Reference: [104-001]) proper part of continuant at some time part of continuant at some time continuant