... deducible, in the presence of OVERLAPS+and INSIDE+, by using Rules I, II, and III.Proof. The reader may refer to the proof of Claim 3.2 in Appendix of [23] for theproof of Claim 3.9.Therefore, ... spatial relationship “A is left of B”(written as “A left -of B”) in [8] means that the position of the centroid of A is left of that of B (and we say “A left -of B” is relative), whereas in [16] ... semantics of spatial relationship symbols right -of, below, and in- front -of aredefined similarly. Notice that these relationship symbols right -of, below, and in-front- of are actually duals of left -of, ...