Particular case where the sub-system is itself monovariant

Particular Case where the Sub-system is itself Monovariant.f 

If the sub-system also is monovariant, then it is indifferent in all its states and the indifferent line of the sub-system is also its equilibrium line. It then follows from the theorem of 17 that the projection of the mono variant line of the parent system on the T,p) plane is coincident with the projection of the monovariant line of the sub-system. 

The Morey-Schreinemakers theorem when applied to this case may be written The monovariant curves of all mono variant systems which have a monovariant sub-system in common, are coincident when projected on the T, p) plane. 

An example of this behaviour is found in the five component, four phase system  

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