Exterior (topology) - Properties

Properties

Many properties follow in a straightforward way from those of the interior operator, such as the following.

  • ext(S) is an open set that is disjoint with S.
  • ext(S) is the union of all open sets that are disjoint with S.
  • ext(S) is the largest open set that is disjoint with S.
  • If S is a subset of T, then ext(S) is a superset of ext(T).

Unlike the interior operator, ext is not idempotent, but the following holds:

  • ext(ext(S)) is a superset of int(S).

Read more about this topic:  Exterior (topology)

Famous quotes containing the word properties:

    A drop of water has the properties of the sea, but cannot exhibit a storm. There is beauty of a concert, as well as of a flute; strength of a host, as well as of a hero.
    Ralph Waldo Emerson (1803–1882)

    The reason why men enter into society, is the preservation of their property; and the end why they choose and authorize a legislative, is, that there may be laws made, and rules set, as guards and fences to the properties of all the members of the society: to limit the power, and moderate the dominion, of every part and member of the society.
    John Locke (1632–1704)