text: This section describes the surface coverage when the adsorbate is in liquid phase and is a binary mixture.
  For ideal both phases no lateral interactions, homogeneous surface the composition of a surface phase for a binary liquid system in contact with solid surface is given by a classic Everett isotherm equation (being a simple analogue of Langmuir equation), where the components are interchangeable (i.e. "1" may be exchanged to "2") without change of equation form:
  where the normal definition of multi-component system is valid as follows:
  By simple rearrangement, we get
  This equation describes competition of components "1" and "2".