Order complete


In mathematics, specifically in order theory and functional analysis, a subset A of an ordered vector space is said to be order complete in X if for every non-empty subset S of C that is order bounded in A, the supremum sup S and the infimum inf S both exist and are elements of A.
An ordered vector space is called order complete, Dedekind complete, a complete vector lattice, or a complete Riesz space, if it is order complete as a subset of itself, in which case it is necessarily a vector lattice.
An ordered vector space is said to be countably order complete if each countable subset that is bounded above has a supremum.
Being an order complete vector space is an important property that is used frequently in the theory of topological vector lattices.

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