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Re: [Coq-Club] Simplest example of impredicative Prop?

From: Arnaud Spiwack <aspiwack AT lix.polytechnique.fr>
To: Bas Spitters <spitters AT cs.ru.nl>
Cc: "Benjamin C. Pierce" <bcpierce AT cis.upenn.edu>, coq-club AT inria.fr
Subject: Re: [Coq-Club] Simplest example of impredicative Prop?
Date: Tue, 31 Jul 2012 09:16:55 +0200

Mmm, very clever.

My bad then. I'll have to retract my example.

On 30 July 2012 15:40, Bas Spitters <spitters AT cs.ru.nl> wrote:

> surjectivity is equivalent to being epi in the category of setoids

You need at least a universe to prove this statement:
http://www2.math.uu.se/research/pub/Wilander2.pdf

but if you have a universe the statement can be proved.

Bas

[Coq-Club] Simplest example of impredicative Prop?, Benjamin C. Pierce, 07/25/2012
- Re: [Coq-Club] Simplest example of impredicative Prop?, Adam Chlipala, 07/25/2012
- Re: [Coq-Club] Simplest example of impredicative Prop?, gallais @ ensl.org, 07/25/2012
- Re: [Coq-Club] Simplest example of impredicative Prop?, Chung-Kil Hur, 07/25/2012
- Re: [Coq-Club] Simplest example of impredicative Prop?, Arnaud Spiwack, 07/27/2012
  - Re: [Coq-Club] Simplest example of impredicative Prop?, Bas Spitters, 07/30/2012
    - Re: [Coq-Club] Simplest example of impredicative Prop?, Arnaud Spiwack, 07/31/2012
      - Re: [Coq-Club] Simplest example of impredicative Prop?, Benjamin C. Pierce, 07/31/2012
        
        Re: [Coq-Club] Simplest example of impredicative Prop?, Arnaud Spiwack, 07/31/2012