Math 2.0

Order, lattices, ordered algebraic structures Binary relations and basic order notions Concept

Upper set

Summary

An upper set of a partially ordered set is a subset that contains everything above each of its elements. The dual notion is a lower set, which contains everything below each of its elements. Upper and lower sets are used to define order filters, the Alexandrov topology, and the lattice of down-sets of a poset.

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Further reading

  1. Web https://en.wikipedia.org/wiki/Upper_and_lower_sets
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TagETCE287E2R
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Kindconcept
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MSC06A06
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Changed2 November 2026

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