Remarks on punctual local connectedness
Theory and applications of categories, Tome 25 (2011), pp. 51-63
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We study the condition, on a connected and locally connected geometric morphism $p : \cal E \to \cal S$, that the canonical natural transformation $p_*\to p_!$ should be (pointwise) epimorphic - a condition which F.W. Lawvere called the `Nullstellensatz', but which we prefer to call `punctual local connectedness'. We show that this condition implies that $p_!$ preserves finite products, and that, for bounded morphisms between toposes with natural number objects, it is equivalent to being both local and hyperconnected.
Publié le :
Classification :
Primary 18B25, secondary 18A40
Keywords: axiomatic cohesion, locally conected topos
Keywords: axiomatic cohesion, locally conected topos
@article{TAC_2011_25_a2,
author = {Peter Johnstone},
title = {Remarks on punctual local connectedness},
journal = {Theory and applications of categories},
pages = {51--63},
year = {2011},
volume = {25},
language = {en},
url = {http://geodesic.mathdoc.fr/item/TAC_2011_25_a2/}
}
Peter Johnstone. Remarks on punctual local connectedness. Theory and applications of categories, Tome 25 (2011), pp. 51-63. http://geodesic.mathdoc.fr/item/TAC_2011_25_a2/