Simplify. Express your answer as a single fraction in simplest form. \[ \frac{u}{4}-\frac{t^{4}}{4} \]

To simplify the expression \(\frac{u}{4}-\frac{t^{4}}{4}\), we start by noticing that both terms have a common denominator of 4. We can combine them into a single fraction. \[ \frac{u}{4} - \frac{t^4}{4} = \frac{u - t^4}{4} \] Now that we have a single fraction, we check if the numerator \(u - t^4\) can be simplified further. Since we don't know any specific values or relationships between \(u\) and \(t\), we will consider this expression as our final result. Thus, the simplified expression is: \[ \frac{u - t^4}{4} \]