Sentence:  Furthermore , one can find a neighborhood of Q in which the difference <WSD>function</WSD> is monotone , for since it is analytic it can have only a finite number of extrema in any interval . 
Meaning of the word marked with <WSD> tags:  (mathematics) a mathematical relation such that each element of a given set (the domain of the function) is associated with an element of another set (the range of the function)