Locally convex vector lattice

In mathematics, specifically in order theory and functional analysis, a locally convex vector lattice (LCVL) is a topological vector lattice that is also a locally convex space.[1] LCVLs are important in the theory of topological vector lattices.

Lattice semi-norms

The Minkowski functional of a convex, absorbing, and solid set is a called a lattice semi-norm. Equivalently, it is a semi-norm p such that implies . The topology of a locally convex vector lattice is generated by the family of all continuous lattice semi-norms.[1]

Properties

Every locally convex vector lattice possesses a neighborhood base at the origin consisting of convex balanced solid absorbing sets.[1]

The strong dual of a locally convex vector lattice X is an order complete locally convex vector lattice (under its canonical order) and it is a solid subspace of the order dual of X; moreover, if X is a barreled space then the continuous dual space of X is a band in the order dual of X and the strong dual of X is a complete locally convex TVS.[1]

If a locally convex vector lattice is barreled then its strong dual space is complete (this is not necessarily true if the space is merely a locally convex barreled space but not a locally convex vector lattice).[1]

If a locally convex vector lattice X is semi-reflexive then it is order complete and (that is, ) is a complete TVS; moreover, if in addition every positive linear functional on X is continuous then X is of X is of minimal type, the order topology on X is equal to the Mackey topology , and is reflexive.[1] Every reflexive locally convex vector lattice is order complete and a complete locally convex TVS whose strong dual is a barreled reflexive locally convex TVS that can be identified under the canonical evaluation map with the strong bidual (i.e. the strong dual of the strong dual).[1]

If a locally convex vector lattice X is an infrabarreled TVS then it can be identified under the evaluation map with a topological vector sublattice of its strong bidual, which is an order complete locally convex vector lattice under its canonical order.[1]

If X is a separable metrizable locally convex ordered topological vector space whose positive cone C is a complete and total subset of X, then the set of quasi-interior points of C is dense in C.[1]

Theorem[1]  Suppose that X is an order complete locally convex vector lattice with topology 𝜏 and endow the bidual of X with its natural topology (i.e. the topology of uniform convergence on equicontinuous subsets of ) and canonical order (under which it becomes an order complete locally convex vector lattice). The following are equivalent:

  1. The evaluation map induces an isomorphism of X with an order complete sublattice of
  2. For every majorized and directed subset S of X, the section filter of S converges in (X, 𝜏) (in which case it necessarily converges to ).
  3. Every order convergent filter in X converges in (X, 𝜏) (in which case it necessarily converges to its order limit).

Corollary[1]  Let X be an order complete vector lattice with a regular order. The following are equivalent:

  1. X is of minimal type.
  2. For every majorized and direct subset S of X, the section filter of S converges in X when X is endowed with the order topology.
  3. Every order convergent filter in X converges in X when X is endowed with the order topology.

Moreover, if X is of minimal type then the order topology on X is the finest locally convex topology on X for which every order convergent filter converges.

If (X, 𝜏) is a locally convex vector lattice that is bornological and sequentially complete, then there exists a family of compact spaces and a family of A-indexed vector lattice embeddings such that 𝜏 is the finest locally convex topology on X making each continuous.[2]

Examples

Every Banach lattice, normed lattice, and Fréchet lattice is a locally convex vector lattice.

See also

References

    1. Schaefer & Wolff 1999, pp. 234–242.
    2. Schaefer & Wolff 1999, pp. 242–250.
    • 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. 8 (Second ed.). New York, NY: Springer New York Imprint Springer. ISBN 978-1-4612-7155-0. OCLC 840278135.
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