Möbius Inversion on the Lattice of Flats is a result in [matroid theory](/page/Matroid%20Theory). It formalizes the assertion that let be a finite matroid, let be the Möbius function of the finite poset , and let be functions to an abelian group . If \begin{align } g(F)=\sum {G\leq F} f(G) \end{align } for every flat , then \begin{align } f(F)=\sum {G\leq.