Neoclassical analysis extends methods of classical calculus to reflect uncertainties that arise in computations and measurements. In it, ordinary structures of analysis, that is, functions, sequences, series, and operators, are studied by means of fuzzy concepts: fuzzy limits, fuzzy continuity, and fuzzy derivatives. For example, continuous functions, which are studied in the classical analysis, become a part of the set of the fuzzy continuous functions studied in neoclassical analysis.

The present perfect tense and present perfect continuous tense have very similar use. They can both be used to talk about actions and situations that started in the past and have continued up to the present…..

The future continuous tense is made with will / shall + be + -ing…….

Incorrect: It is raining for two days.
    Correct: It has been raining for two days.
    Incorrect: The baby is sleeping for three hours now.
    Correct: The baby has been sleeping for three hours now.

Here the error lies in using the present continuous instead of the present perfect continuous. We use the present perfect continuous tense to talk about an action which started in the past, has gone on till the present and is still continuing....

To form the continuous tenses

The present participles are used to construct the continuous tense forms.

    I am writing.
    They are coming.
    It was raining.
    She will be sleeping.
…………