 The case that for a quadratic polynomial the unique critical point is strictly preperiodic is only a very special case; in this restricted sense (as described above) this term is used in complex dynamics; a more appropriate term would be Misiurewicz–Thurston points (after William Thurston, who investigated postcritically finite rational maps).A complex quadratic polynomial has only one critical point.By a suitable conjugation any quadratic polynomial can be transformed into a map of the form formula_13 which has a single critical point at formula_14.