The Slimmest Geometric Lattices 205
نویسنده
چکیده
The Whitney numbers of a finite geometric lattice L oí rank r are the numbers W, of elements of rank k and the coefficients if. of the characteristic polynomial of L, for 0 s k £ r. We establish the following lower bounds for the W, and the absolute values w, = (— 1) w, and describe the lattices for which equality holds (nontrivially) in each case: where n = W is the number of points of L.
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تاریخ انتشار 1974