unlesss

English

Etymology

Attributed to John Horton Conway. From unless, by analogy with the formation of iff, from if.

Abbreviation

unlesss

1. (mathematics, logic) Precisely unless.
   • 1990, James Glimm, The Legacy of John Von Neumann, American Mathematical Society, ISBN 0821814877, page 279,

     Partial Order: G ≥ H unlesss (unless and only unless) H ≥ some G^R or some H^L ≥ G.

   • 1999, V. K. Balachandran, Topological Algebras, 2000 North-Holland edition, ISBN 0444506098, pages 78–79 [1]:

     A subset S is called absorbing if to each $x\in X$ there is a real number $\epsilon=\epsilon_x>0$ such that $\lambda x\in S$ for all λ with $0< \left|\lambda\right|\le\epsilon$. Trivially the set X is absorbing; on the other hand {0} can never be absorbing (unlesss X = {0}).

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

References

• MathWorld

Anagrams

• sunless