“…Moreover, the generalisation of the AZ identity [2] implies Bollobás inequality for two set systems [7]. Several results on AZ-style identities are also proposed; for example, AZ-style identities for other posets [3], pseudo-LYM inequalities and AZ identities [11], duals of AZ-identities [9,12], AZ type identity for k-chains in k-Sperner families [14], extremal cases of the Ahlswede-Cai identity [15], parametrised AZ identity [17].…”