8 \begin{section
}{Algorithm
}
9 An example of an algorithm (bogosort) environment.
12 \caption{Sort a list of numbers
}
14 \Require{A list of numbers $L$
}
15 \Ensure{A new, sorted copy $M$ of the list $L$
}
19 \While{$M$ is not sorted
}
20 \State{Rearrange $M$ randomly
}
28 \begin{section
}{Arrow
}
29 The identity operator on $V$ is $
\identity{V
}$. The composition of
30 $f$ and $g$ is $
\compose{f
}{g
}$. The inverse of $f$ is
34 \begin{section
}{Common
}
35 The function $f$ applied to $x$ is $f
\of{x
}$. We can group terms
36 like $a +
\qty{b - c
}$ or $a +
\qty{b -
\sqty{c - d
}}$. Here's a
37 set $
\set{1,
2,
3} =
\setc{n
\in \Nn[1]}{ n
\le 3 }$. Here's a pair
38 of things $
\pair{1}{2}$ or a triple of them
39 $
\triple{1}{2}{3}$. The Cartesian product of two sets $A$ and $B$
40 is $
\cartprod{A
}{B
}$; if we take the product with $C$ as well,
41 then we obtain $
\cartprodthree{A
}{B
}{C
}$. The direct sum of $V$
42 and $W$ is $
\directsum{V
}{W
}$ and the factorial of the number $
10$
45 Here are a few common tuple spaces that should not have a
46 superscript when that superscript would be one: $
\Nn[1]$,
47 $
\Zn[1]$, $
\Qn[1]$, $
\Rn[1]$, $
\Cn[1]$. However, if the
48 superscript is (say) two, then it appears: $
\Nn[2]$, $
\Zn[2]$,
49 $
\Qn[2]$, $
\Rn[2]$, $
\Cn[2]$.
51 We also have a few basic set operations, for example the union of
52 two or three sets: $
\union{A
}{B
}$, $
\unionthree{A
}{B
}{C
}$. And of
53 course with union comes intersection: $
\intersect{A
}{B
}$,
54 $
\intersectthree{A
}{B
}{C
}$.
58 The dual cone of $K$ is $
\dual{K
}$. Some familiar symmetric cones
59 are $
\Rnplus$, $
\Lnplus$, $
\Snplus$, and $
\Hnplus$. If cones
60 $K_
{1}$ and $K_
{2}$ are given, we can define $
\posops{K_
{1}}$,
61 $
\posops[K_
{2}]{K_
{1}}$, $
\Sof{K_
{1}}$, $
\Zof{K_
{1}}$,
62 $
\LL{K_
{1}}$, and $
\lyapunovrank{K_
{1}}$. We can also define $x
63 \gecone_{K
} y$, $x
\gtcone_{K
} y$, $x
\lecone_{K
} y$, and $x
64 \ltcone_{K
} y$ with respect to a cone $K$.
67 \begin{section
}{Convex
}
68 The conic hull of a set $X$ is $
\cone{X
}$; its affine hull is
69 $
\aff{X
}$, and its convex hull is $
\conv{X
}$. If $K$ is a cone,
70 then its lineality space is $
\linspace{K
}$, its lineality is
71 $
\lin{K
}$, and its extreme directions are $
\Ext{K
}$.
75 We can write things like Carathéodory and Güler and $
\mathbb{R
}$.
78 \begin{section
}{Linear algebra
}
79 The absolute value of $x$ is $
\abs{x
}$, or its norm is
80 $
\norm{x
}$. The inner product of $x$ and $y$ is $
\ip{x
}{y
}$ and
81 their tensor product is $
\tp{x
}{y
}$. The Kronecker product of
82 matrices $A$ and $B$ is $
\kp{A
}{B
}$. The adjoint of the operator
83 $L$ is $
\adjoint{L
}$, or if it's a matrix, then its transpose is
84 $
\transpose{L
}$. Its trace is $
\trace{L
}$.
86 The span of a set $X$ is $
\spanof{X
}$, and its codimension is
87 $
\codim{X
}$. The projection of $X$ onto $V$ is $
\proj{V
}{X
}$. The
88 automorphism group of $X$ is $
\Aut{X
}$, and its Lie algebra is
89 $
\Lie{X
}$. We can write a column vector $x
\coloneqq
90 \colvec{x_
{1},x_
{2},x_
{3},x_
{4}}$ and turn it into a $
2 \times 2$
91 matrix with $
\matricize{x
}$. To recover the vector, we use
92 $
\vectorize{\matricize{x
}}$.
94 The set of all bounded linear operators from $V$ to $W$ is
95 $
\boundedops[W
]{V
}$. If $W = V$, then we write $
\boundedops{V
}$
99 \begin{section
}{Listing
}
100 Here's an interactive sage prompt:
102 \begin{tcblisting
}{listing only,
105 listing options=
{language=sage,style=sage
}}
106 sage: K = Cone(
[ (
1,
0), (
0,
1)
])
107 sage: K.positive_operator_gens()
109 [1 0] [0 1] [0 0] [0 0]
110 [0 0],
[0 0],
[1 0],
[0 1]
115 \begin{section
}{Miscellaneous
}
116 The cardinality of the set $X
\coloneqq \set{1,
2,
3}$ is $
\card{X
}
120 \begin{section
}{Proof by cases
}
123 There are two cases in the following proof.
126 The result should be self-evident once we have considered the
129 \begin{case
}[first case
]
130 Nothing happens in the first case.
132 \begin{case
}[second case
]
133 The same thing happens in the second case.
143 \renewcommand{\baselinestretch}{2}
145 Cases should display intelligently even when the
document is
152 \begin{case
}[first case
]
153 Nothing happens in the first case.
155 \begin{case
}[second case
]
156 The same thing happens in the second case.
163 \renewcommand{\baselinestretch}{1}
166 \begin{section
}{Theorems
}
196 \begin{section
}{Theorems (starred)
}
226 \begin{section
}{Topology
}
227 The interior of a set $X$ is $
\interior{X
}$. Its closure is
228 $
\closure{X
}$ and its boundary is $
\boundary{X
}$.