From: Vaughan Pratt <pratt@cs.stanford.edu>
To: categories@mta.ca
Subject: Re: David Benson's questions on terminology
Date: Wed, 29 Nov 2000 01:25:48 -0800 [thread overview]
Message-ID: <200011290925.BAA17540@coraki.Stanford.EDU> (raw)
Universal algebraists (but not category theorists??) call b the _cover_ of
a when a<b with nothing in between. See e.g. the index of such lattice
theory texts as Davey and Priestley or McKenzie, McNulty and Taylor
(Walter). (MM&T distinguish upper cover and lower cover but obviously
an unqualified cover has to mean the upper kind to all but us Aussies.)
In a well-ordered set, "cover" and "successor" are synonymous: an ordinal
is a cover just when it is a successor ordinal.
Managed not to mention reflexivity---oops.
Vaughan Pratt
next reply other threads:[~2000-11-29 9:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-11-29 9:25 Vaughan Pratt [this message]
[not found] <200011281143.LAA22264@koi-pc.dcs.qmw.ac.uk>
2000-11-28 18:57 ` Robert J. MacG. Dawson
2000-11-29 13:12 ` Mamuka Jibladze
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