* Re: Effective epimorphisms and pretopologies
@ 2008-12-03 2:56 David Roberts
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From: David Roberts @ 2008-12-03 2:56 UTC (permalink / raw)
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* Effective epimorphisms and pretopologies
@ 2008-12-02 5:53 David Roberts
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From: David Roberts @ 2008-12-02 5:53 UTC (permalink / raw)
To: Categories list
Hi all,
An effective epimorphism is a map which is the quotient of its kernel
pair. I would like to use the term 'effective pretopology' to denote a
Grothendieck pretopology such that all the covers have the additional
property that they are effective epimorphisms (I'm assuming the
covering families consist of single maps). Has this been done before?
This seems to conflict a little with the notion of effective topology
as defined by Mike Barr in 'On categories with effective unions'.
There the notion of topology is an endomorphism of the subobject
functor. But perhaps someone can enlighten me on this.
David Roberts
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