PlanetPhysics/Sole Sufficient Operator

A sole sufficient operator or a sole sufficient connective  is an operator that is sufficient by itself to define all of the operators in a specified set of operators.

In logical contexts this refers to a logical operator that suffices to define all of the boolean-valued functions, $$f : X \to \mathbb{B}$$, where $$X$$ is an arbitrary set and where $$\mathbb{B}$$ is a generic 2-element set, typically $$\mathbb{B} = \{ 0, 1 \} = \{ \mathrm{false}, \mathrm{true} \}$$, in particular, to define all of the finitary boolean functions, $$f : \mathbb{B}^k \to \mathbb{B}$$.