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Berge's theorem: a matching $M$ is maximum if and only if the graph doesn't have an augmenting path with respect to $M$.

I don't understand this theorem. For instance the following matching is maximum but has an augmenting path, doesn't it?

enter image description here

The matching $M$ is in gold here and the augmenting path is the one in dotted lines.

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An augmenting path must alternate between gold and black, starting and ending with black edges. In this way, if you replace the gold edges with the black edges, you obtain a larger matching. This argument shows that a matching can only be maximum if there is no augmenting path, and Berge's theorem states the inverse direction: if a matching has no augmenting path then it is maximum.

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