[Haskell-cafe] Occult effects...

[Michal J Gajda]

It is easier to understand it if:
1. You give some examples of such monads
2. Describe how this property arises
3. Tell how whether the law is unique or part of a list of laws applicable

Most of mathematics we do is not entirely disconnected from applications.

If I tell you there is a class of monoids `m` over a set of objects `o` :

class Monoid m => T m o where
  i :: o -> t
  c :: t -> o -> Bool

Such that the following laws are satisfied:

Forall x y z m n.
c (i x) x =True
c mempty x = False
c m y = True => c (m <> n) y = True
c n y = True => c (m <> n) y = True

What does it tell you about the definitions?
Can you tell if this set of laws is correctly stated or exhaustive?
Whether it models what I intend to do?
Without further examples could I claim that it may be universal model for
some phenomena f and g?

Or would you rather see some examples or descriptions of i and c operations?


PS you may respond to haskell-cafe, sure. I did not think that my previous
question deserved sharing, but this answer certainly does.
--
  Cheers
     Michał

On Wed, Nov 11, 2020, 14:04 Kim-Ee Yeoh <ky3 at atamo.com> wrote:

> Hi Michal,
>
> How is it hermetic? I think I fully described the property whose name I am
> opening to discussion.
>
> What is lacking in the definition?
>
> Also, do you mind having this discussion at the cafe itself? You are
> probably not the only one with this query.
>
> On Wed, Nov 11, 2020 at 7:37 PM Michał J Gajda <mjgajda at gmail.com> wrote:
>
>> Hi,
>> Your post to haskell-cafe is somewhat hermetic if you do not provide
>> additional examples.
>> What do you use these for?
>> --
>>   Cheers
>>     Michał
>>
> --
> -- Kim-Ee
>
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