Cannabaceae

In mathematics, specifically in functional analysis and order theory, an ordered topological vector space, also called an ordered TVS, is a topological vector space (TVS) X that has a partial order ≤ making it into an ordered vector space whose positive cone is a closed subset of X.[1] Ordered TVSes have important applications in spectral theory.

Normal cone[edit]

If C is a cone in a TVS X then C is normal if , where is the neighborhood filter at the origin, , and is the C-saturated hull of a subset U of X.[2]

If C is a cone in a TVS X (over the real or complex numbers), then the following are equivalent:[2]

  1. C is a normal cone.
  2. For every filter in X, if then .
  3. There exists a neighborhood base in X such that implies .

and if X is a vector space over the reals then also:[2]

  1. There exists a neighborhood base at the origin consisting of convex, balanced, C-saturated sets.
  2. There exists a generating family of semi-norms on X such that for all and .

If the topology on X is locally convex then the closure of a normal cone is a normal cone.[2]

Properties[edit]

If C is a normal cone in X and B is a bounded subset of X then is bounded; in particular, every interval is bounded.[2] If X is Hausdorff then every normal cone in X is a proper cone.[2]

Properties[edit]

  • Let X be an ordered vector space over the reals that is finite-dimensional. Then the order of X is Archimedean if and only if the positive cone of X is closed for the unique topology under which X is a Hausdorff TVS.[1]
  • Let X be an ordered vector space over the reals with positive cone C. Then the following are equivalent:[1]
  1. the order of X is regular.
  2. C is sequentially closed for some Hausdorff locally convex TVS topology on X and distinguishes points in X
  3. the order of X is Archimedean and C is normal for some Hausdorff locally convex TVS topology on X.

See also[edit]

References[edit]

  1. ^ a b c Schaefer & Wolff 1999, pp. 222–225.
  2. ^ a b c d e f Schaefer & Wolff 1999, pp. 215–222.
  • Narici, Lawrence; Beckenstein, Edward (2011). Topological Vector Spaces. Pure and applied mathematics (Second ed.). Boca Raton, FL: CRC Press. ISBN 978-1584888666. OCLC 144216834.
  • Schaefer, Helmut H.; Wolff, Manfred P. (1999). Topological Vector Spaces. GTM. Vol. 8 (Second ed.). New York, NY: Springer New York Imprint Springer. ISBN 978-1-4612-7155-0. OCLC 840278135.

One thought on “Cannabaceae

  1. Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
    View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction

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