2024-04-01 21:50:50 -07:00

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% use [nosolutions] flag to hide solutions.
% use [solutions] flag to show solutions.
\documentclass[
solutions,
singlenumbering
]{../../resources/ormc_handout}
\usepackage{../../resources/macros}
\usetikzlibrary{calc}
\uptitlel{Advanced 2}
\uptitler{\smallurl{}}
\title{Symmetric Groups}
\subtitle{Prepared by Mark on \today{}}
\def\line#1#2{
\draw[line width = 0.3mm, ->, ocyan]
(#1)
-- ($(#1) + (0, -1)$)
-- ($(#2) + (0,1)$)
-- (#2);
}
\begin{document}
\maketitle
\input{parts/0 intro}
\input{parts/1 cycle}
\input{parts/2 groups}
\input{parts/3 subgroup}
\section{Bonus problems}
\problem{}
Show that $x \in \mathbb{Z}^+$ has a multiplicative inverse mod $n$ iff $\text{gcd}(x, n) = 1$
\vfill
\problem{}
Let $\sigma = (\sigma_1 \sigma_2 ... \sigma_k)$ be a $k$-cycle in $S_n$, and let $\tau$ be an arbitrary element of $S_n$. \par
Show that $\tau \sigma \tau^{-1}$ = $\bigl(\tau(\sigma_1), \tau(\sigma_2), ..., \tau(\sigma_k)\bigr)$ \par
\hint{As usual, $\tau$ is a permutation. Thus, $\tau(x)$ is the value at position $x$ after applying $\tau$.}
\vfill
\problem{}
Show that the set $\Bigl\{ (1, 2),~ (1,2,...,n) \Bigr\}$ generates $S_n$.
\vfill
% TODO: (a second day?)
% alternating group
% type and sign and conjugation
% isomorphisms & automorphisms
% automorphism groups
\end{document}