[Agda] ordering uniqueness
Sergei Meshveliani
mechvel at botik.ru
Thu Oct 10 17:05:07 CEST 2013
On Thu, 2013-10-10 at 01:10 +0200, Marco Maggesi wrote:
> Hello!
>
> I'm new to Agda.
> I wrote a proof of the following theorem
> (see
> attached file):
>
>
>
> ordering-uniqueness : {m n : ℕ} {x y : Ordering m n} → x ≡ y
>
> I'd be interested to see if there
> are
> simpler proof
> s of the same fact.
> Also general remarks about idiom and style are welcome.
>
I have an impression that this is a similar problem as I had with the
type
data Power (x : C) (e : Nat)
with the three constructors.
(This represents the algorithm for binary exponentiation. I succeeded
with the proofs based on it. But the proof is lengthy, and using the
library conversion to Bin allows a much shorter proof).
Each type Power x e has a unique value. And I needed to start with a
proof for
e == e' -> (s : Power x e) -> s' : (Power x e') ->
extractV s == extractV s'
And I was forced to write 12 large clauses with the same head function
name. I hoped for using dotted patterns, but failed to make them work.
Regards,
------
Sergei
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