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Author SHA1 Message Date
Marek 9bdacf0ef5
Merge afb654b458 into 81729eca91 2024-02-09 00:58:27 +01:00
Marek afb654b458 Polish the notation for generating sets 2021-09-05 23:42:22 +02:00
Marek a08b7393b4 Avoid associating nonzero elements with groups 2021-09-05 19:04:58 +02:00
Marek 507aed8a54 Change "strict subgroups" to "proper subgroups" 2021-09-05 18:58:45 +02:00
1 changed files with 5 additions and 5 deletions

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@ -48,7 +48,7 @@ and fewer axioms. They also have an identity, which we'll denote as $1$.
[group]: https://en.wikipedia.org/wiki/Group_(mathematics)
[group-axioms]: https://en.wikipedia.org/wiki/Group_(mathematics)#Definition
Any non-zero element $a$ in a group has an _inverse_ $b = a^{-1}$,
Any element $a$ in a group has an _inverse_ $b = a^{-1}$,
which is the _unique_ element $b$ such that $a \cdot b = 1$.
For example, the set of nonzero elements of $\mathbb{F}_p$ forms a group, where the
@ -86,9 +86,9 @@ notation). The order _of the group_ is the number of elements.
Groups always have a [generating set], which is a set of elements such that we can produce
any element of the group as (in multiplicative terminology) a product of powers of those
elements. So if the generating set is $g_{1..k}$, we can produce any element of the group
as $\prod\limits_{i=1}^{k} g_i^{a_i}$. There can be many different generating sets for a
given group.
elements. So if the generating set is $g_{1..n}$, we can produce any element of the group
as $\prod\limits_{i=1}^{n} g_i^{k_i}$ where $k_i \in \mathbb{Z}$. There can be many
different generating sets for a given group.
[generating set]: https://en.wikipedia.org/wiki/Generating_set_of_a_group
@ -168,7 +168,7 @@ also form a group under $\cdot$.
In the previous section we said that $\alpha$ is a generator of the $(p - 1)$-order
multiplicative group $\mathbb{F}_p^\times$. This group has _composite_ order, and so by
the Chinese remainder theorem[^chinese-remainder] it has strict subgroups. As an example
the Chinese remainder theorem[^chinese-remainder] it has proper subgroups. As an example
let's imagine that $p = 11$, and so $p - 1$ factors into $5 \cdot 2$. Thus, there is a
generator $\beta$ of the $5$-order subgroup and a generator $\gamma$ of the $2$-order
subgroup. All elements in $\mathbb{F}_p^\times$, therefore, can be written uniquely as