update notations

This commit is contained in:
Trance-0
2025-11-04 12:43:23 -06:00
parent d24c0bdd9e
commit 614479e4d0
27 changed files with 333 additions and 100 deletions

View File

@@ -92,10 +92,10 @@ Two equivalent ways to constructing a linear code:
- A **parity check** matrix $H\in \mathbb{F}^{(n-k)\times n}$ with $(n-k)$ rows and $n$ columns.
$$
\mathcal{C}=\{c\in \mathbb{F}^n:Hc^T=0\}
\mathcal{C}=\{c\in \mathbb{F}^n:Hc^\top=0\}
$$
- The right kernel of $H$ is $\mathcal{C}$.
- Multiplying $c^T$ by $H$ "checks" if $c\in \mathcal{C}$.
- Multiplying $c^\top$ by $H$ "checks" if $c\in \mathcal{C}$.
### Encoding of linear codes
@@ -144,7 +144,7 @@ Decoding: $(y+e)\to x$, $y=xG$.
Use **syndrome** to identify which coset $\mathcal{C}_i$ that the noisy-code to $\mathcal{C}_i+e$ belongs to.
$$
H(y+e)^T=H(y+e)=Hx+He=He
H(y+e)^\top=H(y+e)=Hx+He=He
$$
### Syndrome decoding
@@ -215,7 +215,7 @@ Fourth row is $\mathcal{C}+(00100)$.
Any two elements in a row are of the form $y_1'=y_1+e$ and $y_2'=y_2+e$ for some $e\in \mathbb{F}^n$.
Same syndrome if $H(y_1'+e)^T=H(y_2'+e)^T$.
Same syndrome if $H(y_1'+e)^\top=H(y_2'+e)^\top$.
Entries in different rows have different syndrome.