Direct Sum Testing: The General Case

Irit Dinur, Konstantin Golubev

A function $f:[n_1]\times \cdots \times [n_d]\to {\mathbb{F}}_2$ is a direct sum if it is of the form $f\left(a_1,\dots ,a_d\right)=f_1(a_1)\oplus \cdots \oplus f_d(a_d),$ for some $d$ fu…