From: Peter Arndt <toposopher@gmail.com>
To: categories@mta.ca
Subject: Two topos questions
Date: Wed, 2 Nov 2005 03:53:43 -0300 [thread overview]
Message-ID: <2cc0d36c0511012253p1a15630ay1c0eb35f724905db@mail.gmail.com> (raw)
Hi, category theorists,
1. In a message to the categories list from 15. jan.1997 (that message can
be seen at http://www.mta.ca/~cat-dist/catlist/1999/finite-topos) Lawvere
talks about "the ... internal topos ... which parametrizes the decidable
K-finites". Does anyone know what exactly is that internal topos? Is there
some morphism that can be seen as the indexed family of decidable K-finites
(just like the generic cardinal "is" the indexed family of finite cardinals
and can be used to construct the full internal subcategory of finite
cardinals)?
2. An object Y of a topos is said to have locally a property P if there is
an object Z with global support such that Z*(Y) has the property P. For the
topos of sheaves on a T1-space X (and a property P stable under pullback
along subterminals), I convinced myself that this implies the existence of a
covering of X, such that P holds on the restriction of Y to each open set of
the covering. Can this also be proved for schemes or other classes of
topological spaces, maybe with additional conditions on P?
Thanks a lot!
Peter
next reply other threads:[~2005-11-02 6:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-02 6:53 Peter Arndt [this message]
2005-11-02 21:22 ` Prof. Peter Johnstone
2005-11-03 16:18 wlawvere
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