Boolean derivative

Etymology
Named after (1815–1864), an English mathematician, educator, philosopher and logician.

Noun

 * 1)  With respect to a Boolean variable $$x_i$$: The XOR-sum of the positive and negative Shannon cofactors of the given derived function with respect to $$x_i$$. In symbols: $$ {\partial f \over \partial x_i} (\vec x) = f_{x_i} (\vec x) \oplus f_{\bar x_i} (\vec x)$$.