2
$\begingroup$

In "Introduction to Boolean Algebras" the authors introduce a symbol for the complement of the closure of P, where P is a set in a topological space (Ch. 9, p. 60). This is in the context of discussing regular open sets.

J.B. Rosser introduces a different symbol for the same concept. He writes Cc(P) for the complement of the closure of P. ("Simplified Independence Proofs", p. 15). He also gives no name for this.

I'd like to have a name for the complement of the closure. Am I correct in thinking there is no generally accepted name for it? If there isn't, I'm inclined to call it the "conjugate" of P. Would anyone like to suggest a better name than that?

Thanks.

1 Answers 1

6

This does, indeed, have a name: the exterior of the subset.

  • 0
    I see now that's the term used in "Counterexamples in Topology." Lots better name than "conjugate". Thank you.2011-07-18