# Function Conjunction

A function composed of physical expressions is simply the result of the summations, differences, exponentiations, logarithms, or distributed multiplications or divisions of these physical expressions, or in the simplest case, a function is simply equal to an expression, such as $E(m) = mc^2$, where $E$ is a function of $m$.
The basic idea here is that the electromagnetic potentials $\phi$ and $A$ and their derivatives can be used to derive all electromagnetism.