Determination of SU(4)$_{TC}$ Technicolor Gauge Group from Embedding in Extended Technicolor

In technicolor theories using an SU($N_{TC}$) gauge group, the value of $N_{TC}$ is not, {it a priori}, determined and is typically chosen by phenomenological criteria. Here we present a novel way to determine $N_{TC}$ from the embedding of a one-family technicolor model, with fermions in the fundamental represention of SU($N_{TC}$), in an extended technicolor theory, and use it to deduce that $N_{TC}=4$ in this framework.