  We introduce a universal approach for applying the partition rank method, an
extension of Tao's slice rank polynomial method, to tensors that are not
diagonal. This is accomplished by generalizing Naslund's distinctness indicator
to what we call a partition indicator. The advantages of partition indicators
are two-fold: they diagonalize tensors that are constant when specified sets of
variables are equal, and even in more general settings they can often
substantially reduce the partition rank as compared to when a distinctness
indicator is applied. The key to our discoveries is integrating the partition
rank method with M\"{o}bius inversion on the lattice of partitions of a finite
set. Through this we unify disparate applications of the partition rank method
in the literature. We then use our theory to address a finite field analogue of
a question of Erd\H{o}s, generalize work of Pach et. al on bounding sizes of
sets avoiding right triangles to bounding sizes of sets avoiding right
$k$-configurations, and complement work of Sauermann and Tao to determine lower
bounds on sizes of sets in $\mathbb{F}_p^n$ that must have solutions to a
homogeneous linear equation where many but not all variables are equal.
