A Note on Discrete Conduch
نویسنده
چکیده
The class of functors known as discrete Conduch e brations forms a common generalization of discrete brations and discrete oppbrations, and shares many of the formal properties of these two classes. F. Lamarche 7] conjectured that, for any small category B, the category DCF=B of discrete Conduch e brations over B should be a topos. In this note we show that, although for suitable categories B the discrete Conduch e brations over B may be presented as thèsheaves' for a family of coverings on a category B tw constructed from B, they are in general very far from forming a topos.
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تاریخ انتشار 1999