These indicators are numerous but only a few of them are
commonly referred to. They correspond to the graphical representation of
mathematical calculations. The latter represents the prices evolution,
not their absolute level. They are called oscillators, as they correspond to an
estimate of market tensions and behave like a derivative function.
This aspect is crucial in order to understand the
representation principle of oscillators. For example, a technical indicator
reversing up, getting in an up move after having been heading downward,
expresses the beginning of an upward trend on the stock to which it is related.
Symmetrically, this is the same on the downside. The crossing of a mid-level by
indicators thus expresses a move power at its climax letting expect a lower
trend pace ahead of a reversal.