User:SamSim/TeXSandbox

$$f_n(x) = \left \{ \begin{array}{ll} x - \frac{1}{n} \lfloor nx \rfloor & \text{ if } \lfloor nx \rfloor \equiv 0 \bmod{2} \\ \frac{1}{n} \lfloor nx \rfloor - x + \frac{1}{n} & \text{ if } \lfloor nx \rfloor \equiv 1 \bmod{2} \end{array} \right. $$