-
```
Data/Poset/Internal.hs:32:10: error:
• No instance for (Semigroup PosetOrd)
arising from the superclasses of an instance declaration
• In the instance declaration for ‘Monoid P…
-
Monad 就是自函子范畴上的一个幺半群
但是举了这么些例子,怎么一点也看不出来 monad 与 monoid 的关系呢?倒是很明确 Monad 是个比较特殊的 Functor。
我们需要进一步的抽象才能解释这句话,首先,回顾前面 Monoid 的知识,比如那个 Sum 的 Monoid。
Sum.of(1).append(Sum.of(2)).append(Sum.of(0))…
-
I would like to try and separate the equality stuff from the structure traits. I'm thinking something like this:
``` rust
pub trait MagmaAdditive
: Add
+ Eq
{}
```
would become:
``` rust
pu…
ghost updated
4 years ago
-
see comment here:
https://github.com/twitter/algebird/pull/739#discussion_r343814345
reversing the order of semigroup preserves it being a semigroup, as does putting a constant element between e…
-
Suppose I want to compute automata intersection using Kronecker product. I should to define monoid over set of sets of symbols where intersection is an elementwise operation, and emty set is an identi…
-
This pattern is common in the FP world. The description (in Haskell) can be found here:
* https://medium.com/@jonathangfischoff/the-partial-options-monoid-pattern-31914a71fc67
The idea is the fo…
-
### Your environment
Output of `haskell-language-server --probe-tools` or `haskell-language-server-wrapper --probe-tools`:
```sh
haskell-language-server version: 1.0.0.0 (GHC: 8.8.4) (PATH: /…
-
# Steps to Reproduce
Stick this code at the bottom of Prelude.idr:
```idris
interface Semigroup a => VerifiedSemigroup a where
semigroupOpIsAssociative : (l, c, r : a) -> l (c r) = (l c) …
-
- [解説参考](https://qiita.com/AkariLuminous/items/32cbf5bc3ffb2f84a898)
- [セグ木に載せるやり方まとめ](https://scrapbox.io/magurofly/%E3%82%BB%E3%82%B0%E6%9C%A8%E3%81%AB%E8%BC%89%E3%81%9B%E3%82%8B%E3%82%84%E3%82%8A%…
-
```lean
class IsCommutative (op : α → α → α) where
comm : op x y = op y x
class LeftUnit (α : Type u) extends Mul α
class Monoid (α : Type u) extends LeftUnit α
class CommMonoid (α : Type…