# prove the hand-shaking theorem [closed]

I am given an assignment to prove the hand shaking theorem, I don't know how to prove it.

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You need to add the "homework" tag to your question. It would also help if you added a statement of the hand shaking theorem (you are probably referring to this), and what you have tried so far. – Zev Chonoles Mar 30 '11 at 16:41
Dear leopard, please consider the suggestions that have been given to you by other users: try to write clearly with proper grammar, provide motivation (What have you tried? What is the hand-shaking theorem?, and respond to answers given you (e.g. by accepting them or clarifying your questions with comments). – Akhil Mathew Mar 30 '11 at 16:46
– wok Mar 30 '11 at 16:56
@Akhil-thanks for reminding me ! sometimes i get difficult with it – leopard Mar 30 '11 at 18:54
If leopard hasn't handed in the assignment yet, it's probably too late now. Voting to close. – Gerry Myerson Jun 2 '11 at 12:13

## closed as not a real question by Gerry Myerson, Ross Millikan, t.b., Jonas Meyer, Sivaram Jun 5 '11 at 1:27

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.

i have done this consider the following undirected graph

 A                             B

C                             D


I see that ; deg(A)=2, deg(B)=2 , deg(C)=2, deg(D)=2 number of edges, e=4 then, 2e=8

now, ∑deg=2+2+2+2=8

so, 2e=summation of degree of all vertices on the graph

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 I don't see the edges in your graph. You won't be able to prove the general theorem by looking at specific graphs-there are too many of them. So you either need to have a proof for all graphs at once, or to have an induction proof that builds up graphs from smaller ones. – Ross Millikan Apr 3 '11 at 17:37