an Entity references as follows:
Scope note: This symmetric property associates two instances of E92 Spacetime Volume that have some of their extent in common. Examples: - the "Urnfield" period (E4) overlaps with the "Hallstatt" period (E4) In First Order Logic: P132(x,y) ⊃ E92(x) P132(x,y) ⊃ E92(y) P132(x,y) ⊃ P132(y,x)