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What does E(S)E(S) mean in the bipartite matching lecture?

E(S)E(S) denotes the neighborhood of a subset S of the left-side vertices in the right-side set. It is the set of all right-side vertices adjacent to at least one vertex in S.

Conditions

  • S is a subset of the left-side vertices.
  • Adjacency is taken in the given bipartite graph.

Reasoning, step by step

  1. Identify the subset S of the left-side vertices.
  2. Find all right-side vertices that are connected by an edge to at least one vertex in S.
  3. Collect these right-side vertices into the set E(S)E(S).

Example

The slide writes E(S)E(S) on the right side and later states E(S)E(S) ::= boys adjacent to at least one girl in S.

Common misconceptions

  • Confusing E(S)E(S) with the set of edges incident to S.
  • Thinking that E(S)E(S) includes vertices in S itself.

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Answers are generated from source material and independently checked. Consult the original video or creator if something is unclear.