Set Maximum matching to fill in the blanks (at the end of a task) on the graph.

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  • When considering the maximum matching on a graph, a point with rank 1 can be considered to be included in the maximum matching

  • The edge containing the point with rank 1 is called the “end edge”, and the edge containing the other side of the edge is called the “next edge”.

    • The next edge is zero or more in the general graph
  • When you choose a certain maximum matching

    • 1: If neither the end edge nor the next edge is selected (or the next edge does not exist), then selecting the end edge increases the number of matches by 1
      • In other words, it was never a maximum match to begin with.
    • 2: When an edge is unselected and the next edge is selected, swapping selections does not increase or decrease
      • Thus, the exchanged ones are also the maximum matching
    • 3: Neither the end edge nor the next edge is selected for matching.
    • From 1 and 2, some of the largest matches always have end edges selected.
    • So you can select an edge and remove it.
    • In restricted graphs, this “edge of a blade removal” results in a new [edge of a blade

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