Definition:Triangle Wave

Definition
A triangle wave is a periodic real function $T: \R \to \R$ defined as follows:


 * $\forall x \in \R: \map T x = \begin {cases}

\size x & : x \in \closedint {-\lambda} \lambda \\ \map T {x + 2 \lambda} : & x < \alpha - \lambda \\ \map S {x - 2 \lambda} : & x > \alpha + \lambda \end {cases}$

where $\lambda$ is a given real constant.