clopen

English

Etymology

Blend of closed +‎ open.

Pronunciation

• Rhymes: -əʊpən

Adjective

clopen (not comparable)

1. (topology, of a set in a topological space) Both open and closed.
   • 1990, Gerald A Edgar, Measure, Topology, and Fractal Geometry‎^[1], page 80:

     A subset of a metric space is clopen iff it is both closed and open. A metric space is called zero-dimensional iff there is a base for the open sets consisting of clopen sets.

   • 1999, S. J. Dilworth, On the extensibility of certain homeomorphisms and linear isometries, Krzysztof Jarosz (editor), Function Spaces: Proceedings of the Third Conference on Function Spaces, American Mathematical Society, Contemporary Mathematics, Volume 232, page 124,

     FACT 1. Disjoint closed subsets of $\mathbb {N} ^{\mathbb {N} }$ may be separated by disjoint clopen sets.

   • 2002, D. A. Vladimirov, Boolean Algebras in Analysis‎^[2], page 133:

     Theorem 3. 1) Every two disjoint closed sets in a totally disconnected compact space ${\mathfrak {Q}}$ are separated by disjoint clopen sets.

     2) Every algebra of clopen sets which separates the points of a totally disconnected compact space contains all clopen sets.

Noun

clopen (plural clopens)

1. A pair of work shifts in which a worker works a closing shift one day and then works an opening shift the following day.

   James is on vacation, so I've got to do a clopen this weekend to cover his shifts.

See also

• swing shift

Anagrams

• Coplen