The sum of degrees is the number of endpoints of an edge. Each edge has two endpoints. So the total number of degrees is even. Then, the points with odd degrees must be even, otherwise the total degree is odd.

Prove:

∑d=2v is an even number.

If there are odd nodes with odd degrees, the total degree is odd.

conflict

So there are even points with odd degrees.

I didn't say that. The above is the process ... nothing else.