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- From: Marcus Ramos <marcus.ramos AT univasf.edu.br>
- To: "coq-club AT inria.fr" <coq-club AT inria.fr>
- Subject: Re: [Coq-Club] Help on list lemmas
- Date: Thu, 21 Aug 2014 17:25:55 -0300
Thanks Emilio.
2014-08-19 0:58 GMT-03:00 Emilio Jesús Gallego Arias <emilioga AT cis.upenn.edu>:
Hi Marcus,
Another possibility in addition to the excellent solutions that have
Marcus Ramos <marcus.ramos AT univasf.edu.br> writes:
> I guess the following two list lemmas are correct, however I am not able to
> finish their proofs by myself. In case you have any hints or comments, I
> would be glad to hear about them.
been posted is to use the ssreflect library that I have found useful
when doing certain proofs similar to the ones you sent.
Find my solution, but keep in mind that I am a total newbie:
Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq.
Set Implicit Arguments.
Require Import List.
Lemma skip_hd A d :
forall (i : nat) (l : list A),
hd d (skipn i l) = nth i l d.Proof.
by elim=> [ [] | n IH []].
Qed.
Lemma skip_last A d :
forall (i : nat) (l : list A),
i < length l ->Proof.
last (skipn i l) d = last l d.
elim=> // n IH [|x [|y l]] // Hlt.
by rewrite IH.
Qed.
Best,
Emilio
- [Coq-Club] Help on list lemmas, Marcus Ramos, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, Arthur Azevedo de Amorim, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, Marcus Ramos, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, John Wiegley, 08/18/2014
- Re: [Coq-Club] Help on list lemmas, Marcus Ramos, 08/21/2014
- Re: [Coq-Club] Help on list lemmas, John Wiegley, 08/18/2014
- Re: [Coq-Club] Help on list lemmas, Gabriel Scherer, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, Marcus Ramos, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, Cédric, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, Marcus Ramos, 08/21/2014
- Re: [Coq-Club] Help on list lemmas, Cédric, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, Marcus Ramos, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, Marcus Ramos, 08/17/2014
- Re: [Coq-Club] Help on list lemmas, Emilio Jesús Gallego Arias, 08/19/2014
- Re: [Coq-Club] Help on list lemmas, Marcus Ramos, 08/21/2014
- Re: [Coq-Club] Help on list lemmas, Arthur Azevedo de Amorim, 08/17/2014
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