text: The Simon–Glatzel equation is a monotonically increasing function. It can only describe the melting curves that rise indefinitely with increasing pressure. It may fail to describe the melting curves with a negative pressure dependence or local maximums. A damping term that asymptotically slopes down under pressure,  (c is another component-specific parameter), is introduced by Vladimir V. Kechin to extend the Simon–Glatzel equation so that all melting curves, rising, falling, and flattening, as well as curves with a maximum, can be described by a unified equation:
  where  is the Simon–Glatzel equation (rising) and  is the damping term (falling or flattening).
  The unified equation may be rewritten as:
  This form predicts that all solids have a maximum melting temperature at a positive or (fictitious) negative pressure.