An arithmetic read-once formula (ROF) is a formula (circuit of fan-out
1) over
$+, \times$ where each variable labels at most one leaf.
Every multilinear polynomial can be expressed as the sum of ROFs.
In this work, we prove, for certain multilinear polynomials,
a tight lower bound on the number of summands in such an expression.

Added an exponential lower bound over any field.

An arithmetic read-once formula (ROF) is a formula (circuit of fan-out
1) over
$+, \times$ where each variable labels at most one leaf.
Every multilinear polynomial can be expressed as the sum of ROFs.
In this work, we prove, for certain multilinear polynomials,
a tight lower bound on the number of summands in such an expression.

An arithmetic read-once formula (ROF) is a formula (circuit of fan-out
1) over
$+, \times$ where each variable labels at most one leaf.
Every multilinear polynomial can be expressed as the sum of ROFs.
In this work, we prove, for certain multilinear polynomials,
a tight lower bound on the number of summands in such an expression.