biparty graph



This slide is about formally defining “bipartite graph”. Here’s how you can explain it, avoiding repetition from the previous page:


🎓 Formal Definition of Bipartite Graph

Core task of this page: From intuitive model → abstract definition.

We just saw an example of a bipartite graph: one side is classrooms, the other is exams, and an edge means “the classroom is big enough to hold the exam.”

Now let’s formally define what a “bipartite graph” is:


📐 Mathematical Definition

  • A graph is called bipartite if:

    • All its vertices $V$ can be divided into two disjoint sets $V_1$ and $V_2$,
    • And every edge $(u, v)$ satisfies:

      • One endpoint comes from $V_1$, the other from $V_2$.

In other words: Edges can only connect “different types”, never “the same type.”


🖼 Graph Illustration

  • Left side: classrooms $V_1$, right side: exams $V_2$
  • If classroom $i$ can hold exam $j$, draw an edge from $i$ to $j$

The diagram also preserves:

  • The drawing style where $|V_1| = |V_2|$ (though not required)
  • Edge direction is just for semantics, mathematically it can be ignored (undirected edge)

💡 Summary & Transition

The focus here is to establish a formal language, so we can introduce:

  • Matching
  • Maximum Matching
  • Matching Algorithm

You can summarize this slide with a sentence as a transition:

“With this ‘who can host whom’ bipartite model, our next question is: how do we assign classrooms to ensure as many exams as possible can be scheduled?”

Do you need me to prepare a script for the next page on “maximum matching”?

This slide is about the Bipartite Matching Problem. Let’s explain it point by point:


💡 Text Section Explanation

  • "A matching is a subset of the edges for which every vertex belongs to at most one of the edges."

    Translation: A matching is a subset of edges in the graph, requiring that each vertex belongs to at most one of these edges.

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