Independence system

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In combinatorial mathematics, an independence system is a pair , where is a finite set and is a collection of subsets of (called the independent sets or feasible sets) with the following properties:

  1. The empty set is independent, i.e., . (Alternatively, at least one subset of is independent, i.e., .)
  2. Every subset of an independent set is independent, i.e., for each , we have . This is sometimes called the hereditary property, or downward-closedness.

Another term for an independence system is an abstract simplicial complex.

Relation to other concepts

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