What is connection of degrees of a connected undirected simple graph with Euler graph ? Why it should be all even degree vertices ? yes , I read here "every connected graph of all whose vertices have even degree contain no bridges." . It makes sense, Euler graph should not contain bridges. I found here induction proof. I know that is necessary condition,but I need another formal proof . Can you explain please.
Prove that an Eulerian graph is one in which all vertices have even degree?