Quasi-complete space

Topological vector space in which every closed and bounded subset is complete From Wikipedia, the free encyclopedia

In functional analysis, a topological vector space (TVS) is said to be quasi-complete or boundedly complete[1] if every closed and bounded subset is complete.[2] This concept is of considerable importance for non-metrizable TVSs.[2]

Properties

Examples and sufficient conditions

Every complete TVS is quasi-complete.[7] The product of any collection of quasi-complete spaces is again quasi-complete.[2] The projective limit of any collection of quasi-complete spaces is again quasi-complete.[8] Every semi-reflexive space is quasi-complete.[9]

The quotient of a quasi-complete space by a closed vector subspace may fail to be quasi-complete.

Counter-examples

There exists an LB-space that is not quasi-complete.[10]

See also

References

Bibliography

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