Chord of a tree

My question is what is a exact definition of chord in a tree?? like if we have the following tree:

    a
  b   c
d e  f g

is a tree then dbacg is a chord as I have come to know.. Can ebacg or ebacf also a c开发者_StackOverflow中文版hord???

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As far as I know, there is nothing called chord (or cord) in a tree.

There is a definition of “chord” in general graph, but it operates on cycles. And trees never have cycles by definition, so, following this definition, no tree has a chord.

Maybe your teacher uses that name to mean something that is usually called differently? Did he give you a definition?

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chord is a term used for spanning trees. A spanning tree of a graph G is a subgraph that is a tree and contains all vertices of G with minimum number of edges possible. If T is the set of spanning tree edges, then any graph edge not in T is a chord of the spanning tree.

Also note that a graph can have more than one spanning trees.