unlesss

1990, James Glimm, The Legacy of John Von Neumann, American Mathematical Society, →ISBN, page 279, Partial Order: G ≥ H unlesss (unless and only unless) H ≥ some Gᴿ or some Hᴸ ≥ G.

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 ≥ H unlesss H ≥ Gᴿ or Hᴸ ≥ G for some Gᴿ ∈ Gᴿ or some Hᴸ ∈ Hᴸ. ¶ (Analogous to “iff”, the term “unlesss” means “unless and only unless”.)