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A 4-cycle, which denotes the graph below,*---------* | | | | | | *---------*
has the following two properties:
(1) If two points are connected, they have no common neighbors.
(2) If two points are not connected, they have exactly two common neighbors.
Find a graph with more than four vertices that has these two properties.© Copyright 1999 Stan Wagon. Reproduced with permission.