A subset is called absorbing if to each there is a real number such that for all with . Trivially the set is absorbing; on the other hand can never be absorbing (unlesss).
2004, William Fraser, Susan Hirshberg, and David Wolfe, "The Structure of the Distributive Lattice of Games Born by Day n", in Integers: Electronic Journal of Combinatorial Number Theory 5(2) (2005), page 2,
G ≥ HunlesssH ≥ GR or HL ≥ G for some GR ∈ GR or some HL ∈ HL. ¶ (Analogous to “iff”, the term “unlesss” means “unless かつ only unless”.)