“…The axiom (J0) first appeared in [24] for characterizing the interval function of trees. The axiom is discussed in [4] for characterizing the interval function of a Ptolemaic graph G. We may observe that both the family of bridged graphs BG and distance hereditary graphs DH is a strict super class of the family of Ptolemaic graphs,PG, that is, PG DH and PG BG and BG and DH coincide only in PG. But, BG DH and DH BG, This relation is also reflected in the implications between the axioms (J0), (J2 ′ ), (J3 ′ ) and (J0 ′ ).…”