Scope note: This property associates an instance of E4 Period with another instance of E4 Period that falls within the spacetime volumes occupied by the latter.In other words, all points in the former are also points in the latter. This property is transitive. Examples: - the Great Plague (E4) falls within The Gothic period (E4) In First Order Logic: P10(x,y) ⊃ E92(x) P10(x,y) ⊃ E92(y)