LitTex is an *archival* markup language
that renders to both LaTeX and HTML.

It was designed by N. C. Landolfi for the Litterae and Bourbaki projects.

Here is an example, from Section 1 of
Halmos’ *Naive Set Theory*.

```
¶ ⦊
‖ The principal concept of set theory, the one that in
completely axiomatic studies is the principle primitive
(undefined) concept, is that of ‹belonging›. ⦉
‖ If $x$ belongs to $A$ ($x$ is an element of $A$, $x$
is contained in $A$), we shall write
◇ ⦊
‖ x ∈ A. ⦉
⦉⦉
‖ This version of the Greek letter epsilon is so often
used to denote belonging that its use to denote
anything else is almost prohibited. ⦉
‖ Most authors relegate $ϵ$ to its set-theoretic use
forever and use $ε$ when they need the fifth letter of
the Greek alphabet. ⦉
⦉
```

LitTex is *readable*, *short*, and
*has math*.

What can LitTex render? Well, this page, for instance.

Closing elements are denoted by ⦉. See examples below.

Runs are denoted by ‖.

Example 1

` ‖ This is a run. ⦉`

Example 2
‖ The fun part is that runs can be multiple lines of
plain unicode text 🙂, but the lit program will format
them, and have them wrap nicely (in fact, it formatted
this block you are reading). ⦉

Footnotes are denoted by †.

Example 1: Kierkegaard’s Journal

```
¶ ⦊
‖ What I really need is to get clear about what I must
do,
† ⦊
‖ How often, when a person believes that he has the
best grip on himself, it turns out that he has
embraced a cloud instead of Juno. ⦉
⦉
not what I must know, except insofar as knowledge must
precede every act. ⦉
‖ What matters is to find a purpose, to see what it
really is that God wills that ‹I› shall do; the
crucial thing is to find a truth which is truth ‹for
me›,
† ⦊
‖ Only then does one have an inner experience, but
how many experience life’s different impressions the
way the sea sketches figures in the sand and then
promptly erases them without a trace. ⦉
⦉
to find ‹the idea for which I am willing to live and
die›. ⦉
⦉
```

Display math blocks are denoted by ◇.

Example 1:

```
◇ ⦊
‖ ∫ f dμ = ∫ f^+ dμ - ∫ f^- dμ. ⦉
⦉
```

Example 2:
◇ ⦊
‖ (X, ℱ, 𝗣) ⦉
⦉

Paragraphs are denoted by ¶.

Example 1:

```
¶ ⦊
‖ Here it is. ⦉
‖ You can put math
◇ ⦊
‖ x^2 + y^2 = 1 ⦉
⦉
where it ought to go. ⦉
⦉
```

List items are denoted by ‣. See examples below.

Unordered lists are denoted by ⁝.

Example 1

```
⁝ ⦊
‣ apples ⦉
‣ oranges ⦉
‣ and something more complicated
◇ ⦊
‖ ax^2 + bx + c = 0 ⦉
⦉⦉
⦉
```

Ordered lists are denoted by 𝍫.

Example 1

```
𝍫 ⦊
‣ did you know ⦉
‣ you can escape these \‖ \⦉ ⦉
⦉
```

Sections are denoted by §

Example 0

```
§ This is a section. ⦉
§§ This is a subsection. ⦉
§§§ This is a subsubsection. ⦉
#§ This one is numbered ⦉
#§§ And this one ⦉
```

Example 1

```
§ Why ⦉
¶ ⦊
‖ It happens that all circulant matrices have the same
eigenvectors. ⦉
⦉
§ Definition ⦉
¶ ⦊
‖ Recall that if $C$ is circulant then
◇ ⦊
‖ C = c_0I + c_1 S + c_2S^2 + ⋯ + c_{n-1}S^{n-1}. ⦉
⦉⦉
‖ So $q ∈ 𝗥^d$ is an eigenvector of $C$ if and only
if it is one of $S$.
† ⦊
‖ Future editions will complete this development. ⦉
⦉⦉
⦉
```

Example 2.

```
§ Definition ⦉
¶ ⦊
‖ Let $(X, 𝗙)$ be a vector space where $𝗙$ is the
field of real numbers or the field of complex numbers. ⦉
‖ The functional $f: X → 𝗥$ is a ❬norm❭ if
𝍫 ⦊
‣ $f(v) ≥ 0$ for all $x ∈ V$ ⦉
‣ $f(v) = 0$ if and only if $x = 0 ∈ X$. ⦉
‣ $f(α x) = \abs{α}f(x)$ for all $α ∈ 𝗙$, $x ∈ X$ ⦉
‣ $f(x + y) ≤ f(x) + f(y)$ for all $x, y ∈ X$. ⦉
⦉⦉
⦉
```

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Reserved.