Sentence:  Here, R is rank formula of composition – a sequence of components by reduction of their value (contents); Н is Shannon information entropy – complexity measure; А – <WSD>anentropy</WSD> – measure of purity; Т – tolerance – measure of ultrapurity. 
Meaning of the word marked with <WSD> tags:  (uncountable) A measure of the simplicity or purity of a distribution.