In Brazilian Portuguese, two types of reduced sentences of infinitive are existing: one that includes a personal number morphology and one without any inflection. The inflected infinitive, called personal infinitive or inflected infinitive has been for a long time a problem for researchers on language, fact that left some questions remaining. Our study aims to present some of these problems on the grammatical tradition, which did not find an harmonious way to describe the contexts of bending infinitives occurrence, either by linguistics, which does not adopt a unified theory, since many researches address the problem differently. For this reason, we will cover the traditional grammar and linguistics view in a way to present the problem as ...