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From: Paul B Levy <P.B.Levy@cs.bham.ac.uk>
To: categories@mta.ca
Subject: Re: topos logic arising nicely
Date: Mon, 9 Jun 2003 10:18:11 +0100 (BST)	[thread overview]
Message-ID: <Pine.LNX.4.44.0306091006420.7512-100000@acws-0092.cs.bham.ac.uk> (raw)
In-Reply-To: <200306051946.VAA19086@fb04305.mathematik.tu-darmstadt.de>

On Thu, 5 Jun 2003, Thomas Streicher wrote:

> Hi Paul,
>
> > "The neglect of sum types is the root of all evil."
>
> To some extent this may be true for programming languages (but see recent
> work of Jim Laird). For logics it is less clear. Actually you mean the
> empty type, isn't it?

which is the n=0 instance of the n-ary sum connective.  So it should be
included in even the simply typed setting.

Paul

> Moreover, sunset types are slightly heavier than
> ordinary sum types. Subset types are rather dependent sum types.







  reply	other threads:[~2003-06-09  9:18 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-06-05 19:46 Thomas Streicher
2003-06-09  9:18 ` Paul B Levy [this message]
  -- strict thread matches above, loose matches on Subject: below --
2003-06-09 20:03 Thomas Streicher
2003-06-05 11:08 Thomas Streicher
2003-06-06  9:29 ` Hendrik Tews
2003-06-08 11:39   ` Thomas Streicher
2003-06-03 20:14 Thomas Streicher
2003-06-04 15:20 ` Toby Bartels
2003-06-04 15:42 ` Paul B Levy

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