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Homework Help: Graph orientation- combinatorics?

  1. Mar 8, 2012 #1
    1. The problem statement, all variables and given/known data

    I have a graph, with 4 vertices and 4 edges, i.e. a square. I need to find all non-isomorphic orientations of this graph.

    2. Relevant equations
    "Orientation of a graph arises by replacing each edge {x,y} by one of the arcs (x,y) or (y,x)."

    3. The attempt at a solution

    I need help understanding this, i'm not sure how to tell if they are not isomorphic. I know what isomorphic is, but in this case it's just a square, are squares with different directions non isomorphic? So I just change the directions of the arcs? (Note: arc means edge) Any help is appreciated. Thanks.
  2. jcsd
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