The Coq mailing list

[Altenkirch Thorsten <psztxa AT exmail.nottingham.ac.uk>]

I use this example in
http://www.cs.nott.ac.uk/~txa/talks/nbe09.pdf

which also explains the relationship to normalisation.

T.

On 18/04/2014 12:02, "Matej Kosik"
<5764c029b688c1c0d24a2e97cd764f AT gmail.com>
 wrote:

>Hi all,
>
>I am slowly going through the CoqArt book.
>In Section 3.7.2 it is claimed that Peirce's formula
>
>    ((P -> Q) -> P) -> P
>
>is not provable (in Coq).
>
>I am curious, how does the proof (of Pierce's formula unprovability in
>Coq) look like?
>(up to that point, all concepts and exercises seem clear).
>
>Thanks in advance for whatever help.

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