. Lemma-36, Let x be a node If d t (x) ? 9

. Proof, Assume d t (x) = 6. Then x sends no charge by Rules 3 because ?(x) = ?2

. Lemma-38, Let x be a node

. Proof, Assume d t (x) = 7. Then x sends no charge by Rules 3 because ?(x) = 0

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