Dowling geometry

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Generalizations: Add full G-expansions of graph.

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==Generalizations==
==Generalizations==


There is also a Dowling geometry, of rank 3 only, associated with each [[quasigroup]]; see Dowling (1973b). This does not generalize in a straightforward way to higher ranks. There is a generalization due to Zaslavsky (2012) that involves ''n''-ary quasigroups.
There is also a Dowling geometry, of rank 3 only, associated with each [[quasigroup]]; see Dowling (1973b). This does not generalize in a straightforward way to higher ranks. There is a further generalization due to Zaslavsky (2012) that involves ''n''-ary quasigroups.

A different generalization due to Zaslavsky (1991) is obtained from the full <math>G</math>-expansion of an arbitrary graph <math>\Gamma</math>. This gain graph has lattice obtained from the Dowling lattice by excluding all partial partitions such that the induced subgraph on some ''B<sub>i</sub>'' is disconnected. The characteristic polynomial of this matroid is obtained from the chromatic polynomial <math>\chi_\Gamma(t)</math> of <math>\Gamma</math> by substituting <math>t = (y-1)/|G|</math> and normalizing to a monic polynomial.


==References==
==References==
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