Pre-segmented TC

In some strong TC domains, it may be possible to obtain more information than just a sequence of classes; we may also be provided with a function $\mathit{Seg}: \mathit{SS} \rightarrow T_{\mathit{SS}}^*$, where $T_{\mathit{SS}}$ is the union of the domains of all the elements of $\mathit{SS}$, in other words, all the possible timepoints in the data. This function returns the ``breakpoints'' between different classes in the class sequence. For example, if the strong TC domain is sign language, this function $\mathit{Seg}$ when applied to a single stream, would return all the times when one sign ends and another begins. In general if there are $n$ classes in the class sequence, $\mathit{Seg}$ will return a sequence of $n-1$ time points.

In some domains, such information is provided in a slightly different form. Rather than return a single point in time, $\mathit{Seg}$ returns a tuple, representing an interval, during which a ``transition'' from one class to another occurs. The first element of the tuple represents the start of the transition, and the second represents the end of the transition.