Editing Möbius inversion formula (section)

==Contributions of Weisner, Hall, and Rota==
{{Quotation|
The statement of the general Möbius inversion formula [for partially ordered sets] was first given independently by [[Louis Weisner|Weisner]] (1935) and [[Philip Hall]] (1936); both authors were motivated by group theory problems. Neither author seems to have been aware of the combinatorial implications of his work and neither developed the theory of Möbius functions. In a fundamental paper on Möbius functions, [[Gian-Carlo Rota|Rota]] showed the importance of this theory in combinatorial mathematics and gave a deep treatment of it. He noted the relation between such topics as inclusion-exclusion, classical number theoretic Möbius inversion, coloring problems and flows in networks. Since then, under the strong influence of Rota, the theory of Möbius inversion and related topics has become an active area of combinatorics.<ref>{{Harvnb|Bender|Goldman|1975|pp=789–803}}</ref>
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