The propeller conjecture asserts that three planar sectors of angle maximize the sum of squared Gaussian first moments over
measurable partitions, after extension in orthogonal
directions. Precisely, if
is the standard Gaussian
measure on
,
the proposed bound for a set partition
into measurable
sets is
The first moments are unnormalized vectors, and the norms are Euclidean. Cell probabilities
are unrestricted, and empty cells are allowed. For and
, the three sectors, multiplied by their orthogonal
complement, attain
, with any remaining cells empty.