A Note about Shellable Planar Posets
نویسنده
چکیده
We will show that shellability, Cohen-Macaulayness and vertexde composability of a graded, planar poset P are all equivalent with the fact that P has the maximal possible number of edges. Also, for a such poset we will find an R−labelling with {1, 2} as the set of labels. Using this, we will obtain all essential linear inequalities for the flag h−vectors of shellable planar posets from [1]. AMS Mathematics Subject Classification (2000):
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